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This Campbell's string bean casserole recipe delivers the nostalgic comfort of a classic family dinner with a crispy, cheesy top that always disappears first. 💛 Growing up in a Boston triple-decker, I remember my Nonna making this dish on chilly evenings—simple ingredients, rich flavors, and that perfect golden crust.
The secret lies in the balance of Campbell's condensed cream of mushroom soup and the creamy cheese topping that bakes to golden perfection.
What makes this recipe special is how it transforms humble string beans into a hearty, satisfying meal in just one baking dish. The combination of tender green beans, creamy soup, and that irresistible crispy cheese topping creates a dish that feels like a warm hug on a plate.
It's the kind of recipe that brings people together—whether for a family dinner or a potluck gathering.
The result is a casserole with a crispy, golden-brown cheese crust that contrasts beautifully with the creamy filling underneath. Every bite delivers tender beans, rich soup, and that satisfying crunch from the top.
This is comfort food at its finest—simple to prepare but packed with flavor that makes it unforgettable.
Perfect for weeknight dinners or holiday gatherings, this casserole scales easily to feed a crowd. The best part? It's a one-dish wonder, so cleanup is a breeze. Let's get started on this timeless classic that never fails to impress.
Ingredients for campbell's string bean casserole
Six simple ingredients transform into Nonna's legendary cheesy, crispy string bean casserole every time.
| Ingredient | Amount | Notes |
|---|---|---|
| Campbell's Cream of Mushroom Soup 🍄 | 2 cans | Condensed, 10.5 oz each can |
| String Beans 🌱 | 2 ½ lbs | Fresh or frozen, trimmed |
| Sharp Cheddar Cheese 🧀 | 2 cups | Shredded, sharp flavor preferred |
| Milk 🥛 | ½ cup | Whole milk for creaminess |
| Butter 🧈 | ½ cup | Unsalted, melted |
| All-Purpose Flour 🌾 | ¼ cup | For topping crispiness |
| Yellow Onion 🧅 | 1 whole | Medium size, diced fine |
| Garlic Cloves 🧄 | 3 cloves | Minced for aromatic base |
| Salt 🧂 | 1 tsp | Kosher salt preferred |
| Black Pepper 🌶️ | ½ tsp | Freshly ground for heat |
| Breadcrumbs 🍞 | ½ cup | Plain or panko style |
| Fresh Parsley 🌿 | ¼ cup | Chopped, for garnish |
The Campbell's soup is the heart of this dish—grab the condensed version from any grocery store aisle. I always check the expiration date though, since older cans lose that rich, creamy texture. Wegmans or Trader Joe's have the freshest stock if you're picky. The string beans? Fresh is ideal, but frozen works perfectly—just thaw and drain well. For the cheese, sharp cheddar is non-negotiable—it melts better and gives that perfect tang. I buy the block and shred it myself (pre-shredded gets gummy), or grab the Boar's Head brand if I'm short on time.
No Campbell's soup? Homemade mushroom cream sauce works—just sauté mushrooms, garlic, and onion, then blend with milk and butter. Running low on cheddar? Mozzarella mixed in adds stretch, but keep at least half cheddar for that classic flavor. The breadcrumbs can be any kind—panko for extra crunch or regular for a softer top. Fresh parsley is pretty, but dried works in a pinch (use half the amount). Pro tip: Toast the breadcrumbs in butter before adding to the casserole for next-level crispiness.
This casserole reheats like a dream—350°F for 15 minutes until bubbly. Leftovers keep 4-5 days in the fridge, but honestly, it's better the next day when flavors meld. For make-ahead magic, assemble the casserole, refrigerate overnight, then bake straight from cold. The crust gets even crispier that way. Portion into 8x8 glass dishes for easy reheating—just pop in the microwave for 2 minutes if you're in a rush.
Why You'll Love This Recipe
- Here’s what sold me: I already had everything in my fridge except the string beans, which cost less than a coffee. No specialty ingredients, no last-minute grocery runs—just open a can, dump in the soup, and let the cheese do the work. Budget-friendly doesn’t mean boring, and this proves it.
- Five-Ingredient Magic: I swear, this is the kind of recipe where you might peek at the ingredients and think, "That’s it?" But that creamy mushroom soup base—thickened with butter and milk—turns those simple string beans into something rich and satisfying. The sharp cheddar on top? Pure umami payoff with zero effort.
- Crowd-Pleaser Guaranteed: Between us, this is the dish that makes my in-laws ask for the recipe every time. Kids love the cheesy top layer, adults adore the deep savory notes from the soup, and even my picky uncle (who "doesn’t eat casseroles") finishes his plate. It’s weirdly universal—like comfort food with a secret handshake.
- Leftovers That Don’t Suck: Honestly, I make this on Sunday because reheating it is zero stress. The cheese stays melty, the beans stay tender, and it’s still delicious straight from the fridge—no sad, dry edges here. I’ll pack it for lunches or freeze portions for when I’m too tired to cook. (Yes, even on a Tuesday night.)
Step-by-step instructions for Campbell's string bean casserole
Here's how to make the ultimate cheesy, crispy-topped masterpiece that'll have everyone begging for seconds.
🍳 Step 1: Sauté the Flavor Base
Melt the 0.5 cup butter in a large skillet over medium heat. Add the 1 whole yellow onion (diced fine) and cook for 5 minutes until softened and translucent. Here's the thing—don't rush this. You want the onion to caramelize just a bit for that sweet depth of flavor.
Stir in the 3 cloves garlic cloves (minced) and cook for another 30 seconds until fragrant. That garlic aroma is the secret to making this casserole taste restaurant-quality. Remove from heat and set aside—this aromatic base will be the flavor foundation for your entire dish.
🥘 Step 2: Prepare the String Beans
If using fresh 2.5 lbs string beans, trim the ends and cut into 1-inch pieces. For frozen, just drain and pat dry. In a large bowl, combine the prepared string beans with the sautéed onion and garlic mixture. Add 1 tsp salt and 0.5 tsp black pepper, and toss everything together until the beans are evenly coated.
Here's where it gets fun—give the beans a good taste test. They should be seasoned perfectly now, but you can adjust the salt and pepper to your preference. I like mine with a little extra kick, so I might add a pinch more pepper at this stage. This is your chance to make it your own before we lock in those flavors with the sauce.
🍲 Step 3: Build the Creamy Sauce
In a separate bowl, whisk together the 2 cans Campbell's cream of mushroom soup, 0.5 cup milk, and 2 cups sharp cheddar cheese until completely smooth. The cheese should melt into the soup completely—this is your creamy base that'll make every bite irresistible. If you're using pre-shredded cheese, give it a quick stir to break up any clumps.
Pour this creamy mixture over the prepared string beans in your bowl. Stir gently but thoroughly to combine everything. You're looking for an even distribution of sauce throughout the beans—this ensures every bite will be packed with that cheesy goodness. Don't worry if it looks a bit watery now; it'll thicken up beautifully in the oven.
🔥 Step 4: Assemble and Bake to Perfection
Preheat your oven to 375°F. Transfer the string bean mixture to a greased 9x13-inch baking dish. Spread it out evenly—this helps create that even, golden-brown top we're after. Here's the moment that matters: sprinkle the 0.25 cup all-purpose flour evenly over the top of the casserole.
In a small bowl, mix together the 0.5 cup breadcrumbs with 1 tablespoon melted butter (save the rest for later). Sprinkle this mixture evenly over the flour. The breadcrumbs will create that incredible crispy top we're all craving. Bake uncovered for 45-50 minutes until the top is golden brown and bubbly, and the edges are set.
🍽️ Step 5: Finish with Crispy Top and Fresh Garnish
Let the casserole rest for 5 minutes after removing from the oven. This resting time is crucial—it allows the top to set properly and prevents it from falling apart when you serve it. While it's resting, melt the remaining 0.25 cup butter in a small saucepan over low heat.
Once the casserole has rested, pour the melted butter evenly over the top. The heat from the casserole will make this butter sizzle and create an even more golden, crispy finish. Sprinkle with the 0.25 cup chopped fresh parsley for that pop of color and freshness. Serve immediately while the top is still crispy—this casserole is best enjoyed straight from the oven!
Pro Tips For Making Campbell'S String Bean Casserole
- Melt the Butter First: I learned this the hard way—adding cold butter straight to the hot soup just makes it clump like a sad science experiment. Melt the butter in the baking dish first, then stir in the soup and milk. The sauce will be smoother, and the flavor will blend better.
- Trim the String Beans: String beans are called that for a reason, and those little fibers are annoying. Take 5 minutes to snap off the ends and pull out any tough strings before adding them to the casserole. It’s not glamorous, but your mouth will notice the difference.
- Skip the Pre-Cooked Beans: The recipe might call for canned beans, but fresh or frozen string beans cooked just until tender-crisp make this dish feel lighter and more vibrant. Boil them for 4-5 minutes before mixing—just enough to soften, not turn them to mush.
- Bake Until Bubbly: After sprinkling the cheese, resist the urge to pull it out early. Bake until the edges are golden and the center bubbles for 5 minutes—no peeking! Underbaking leaves a sad, soupy mess, while overbaking turns the cheese rubbery. Trust the timer.
Make-ahead tips for campbell's string bean casserole
Prep Ahead Strategy
This casserole is a make-ahead dream—assemble the entire dish in your 9x13-inch baking dish up to 24 hours before baking. Cover tightly with plastic wrap and refrigerate. The flavors meld beautifully overnight, and the crust turns out even crispier when baked straight from the fridge.
I always do this for holiday gatherings—just pop it in the oven when guests arrive. 💫
Freezer-Friendly Method
For longer storage, assemble the casserole and freeze it completely before baking. Use a freezer-safe baking dish or transfer to a heavy-duty aluminum pan. Wrap tightly with plastic wrap and foil, then freeze for up to 3 months.
When ready to bake, thaw overnight in the fridge, then bake as directed (add 10-15 extra minutes to the baking time).
Portion Control Tips
Divide the assembled casserole into individual 8x8-inch glass dishes for easy reheating. Portion the sauce and beans evenly, then top with breadcrumbs and flour. Bake at 375°F for 30-35 minutes—these single servings reheat perfectly for quick lunches.
I keep these in my freezer for busy weeknights when I need a satisfying meal without the fuss. ✨
Breadcrumbs Prep Shortcut
Save time by toasting your breadcrumbs in advance. Mix 0.5 cup breadcrumbs with 1 tablespoon melted butter in a bowl, then spread on a baking sheet. Bake at 350°F for 5 minutes until golden.
Store in an airtight container for up to 1 week—these crispy breadcrumbs add instant texture to any casserole. 🍞
Cheese Melting Hack
For extra gooey cheese, sprinkle ¼ cup grated Parmesan over the breadcrumb topping before baking. The Parmesan adds a salty depth that makes the crispy top even more addictive.
I also like adding ½ cup mozzarella to the creamy sauce layer for stretch—just fold it in with the cheddar before pouring over the beans.
Oven Temperature Tips
If your oven runs hot, reduce the temperature to 350°F and bake for 55-60 minutes. For a deeper flavor, broil for 2-3 minutes at the end of baking—just watch closely to avoid burning.
I test doneness by inserting a toothpick; it should come out with a few moist crumbs, not liquid. The top should be golden brown with just a hint of browning on the edges. 🔥
Nutrition facts
Frequently asked questions
Can I use frozen string beans instead of fresh?
Frozen string beans work perfectly in this recipe. Just thaw and drain them well before using. The texture will be just as tender when baked, and you'll save time on trimming and washing. For best results, pat them completely dry to prevent a watery casserole.
What makes the cheese topping extra crispy?
The secret is the flour-breadcrumb layer. Start with a thin dusting of all-purpose flour over the sauce, then top with a mix of breadcrumbs and melted butter. The flour creates a barrier that prevents sogginess, while the breadcrumbs toast beautifully in the oven. For extra crunch, toast the breadcrumbs in butter before adding them to the casserole.
Can I make this casserole ahead of time?
Yes! Assemble the entire casserole in a baking dish, cover tightly, and refrigerate for up to 24 hours before baking. The flavors meld beautifully overnight, and the crust turns out even crispier. For longer storage, freeze the assembled casserole (unbaked) for up to 3 months. Thaw in the fridge before baking, adding 10-15 extra minutes to the cooking time.
Can I substitute another type of cheese?
Sharp cheddar is ideal, but you can mix in ½ cup mozzarella for extra stretchiness. Avoid pre-shredded cheese—it contains anti-caking agents that make the topping gummy. For a tangy twist, add ¼ cup grated Parmesan to the breadcrumb topping before baking. Just remember, cheddar is the star of this dish!
Why did my casserole turn out watery?
Watery results usually happen when the beans weren't drained well (especially frozen) or the sauce was too thin. Always pat beans completely dry, and if using frozen, let them thaw in a colander. For extra insurance, bake the casserole uncovered for the last 5-10 minutes to evaporate any excess moisture. The top should be golden and crispy, not wet.