Old-School Green Bean Casserole

Featured in: Everyday Favorites

This timeless side dish brings together fresh green beans, savory mushrooms, and golden fried onions for a comforting addition to festive meals. Green beans are blanched to retain their vibrant color, then coated in a creamy mixture of sautéed mushrooms, onion, and garlic, thickened with flour, milk, and cream. Finished with a generous layer of crispy fried onions, the casserole is baked until bubbly and golden. Ideal for holidays and family dinners, it pairs well with roasted turkey or chicken and can be prepared ahead for convenience.

Updated on Sun, 09 Nov 2025 12:07:00 GMT
A nostalgic Old-School Green Bean Casserole topped with crispy fried onions and creamy sauce. Save
A nostalgic Old-School Green Bean Casserole topped with crispy fried onions and creamy sauce. | crumbnest.com

A nostalgic, creamy side dish featuring tender green beans, savory mushrooms, and crispy fried onions—a classic for holiday feasts and family dinners.

I first tasted this casserole at my grandmother's Thanksgiving table, and ever since, it's been a beloved tradition in my family. The aroma and those golden fried onions instantly bring back warm memories of togetherness.

Ingredients

  • Fresh Green Beans: 900 g (2 lb), trimmed and cut into 5 cm (2-inch) pieces (substitute with 900 g frozen cut green beans, thawed and drained)
  • Unsalted Butter: 2 tbsp
  • Cremini or Button Mushrooms: 250 g (9 oz), sliced
  • Yellow Onion: 1 small, finely chopped
  • Garlic Cloves: 2, minced
  • All-Purpose Flour: 2 tbsp
  • Whole Milk: 240 ml (1 cup)
  • Heavy Cream: 120 ml (1/2 cup)
  • Low-Sodium Vegetable Broth: 120 ml (1/2 cup)
  • Salt: 1 tsp
  • Black Pepper: 1/2 tsp
  • Ground Nutmeg (optional): 1/2 tsp
  • Crispy Fried Onions: 150 g (1 1/2 cups), store-bought or homemade

Instructions

Prep Oven:
Preheat the oven to 180°C (350°F).
Blanch Green Beans:
Bring a large pot of salted water to a boil. Add green beans and cook for 5 minutes until just tender but still bright green. Drain and immediately rinse under cold water to stop cooking. Set aside.
Cook Mushrooms & Aromatics:
In a large skillet over medium heat, melt the butter. Add mushrooms and cook for 5-6 minutes until tender and browned. Add onion and garlic, cooking for another 2-3 minutes until softened.
Make Sauce:
Stir in the flour and cook for 1 minute, stirring constantly. Gradually whisk in milk, cream, and broth. Bring to a simmer and cook until thickened, about 5 minutes. Season with salt, pepper, and nutmeg (if using).
Combine Beans & Sauce:
Add the drained green beans to the skillet and toss to coat evenly in the sauce.
Assemble in Baking Dish:
Transfer the mixture to a 2-liter (2-quart) baking dish. Sprinkle half of the crispy fried onions on top.
Bake:
Bake for 25 minutes until bubbling. Remove from oven, top with remaining onions, and bake for 5-7 minutes more until golden and crisp.
Cool & Serve:
Let cool for 5 minutes before serving.
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| crumbnest.com

Whenever I make this casserole, my kids rush to the table to scoop the crispy topping. It's a must-have for our family feast, and leftovers are just as delicious the next day!

Serving Suggestions

Pair your green bean casserole with roast turkey, chicken, or as a hearty side for vegetarian dinners. It also goes perfectly alongside mashed potatoes or stuffing.

Make-Ahead & Storage

You can assemble the casserole up to step six and refrigerate for up to 24 hours. Add the fried onions and bake just before serving. Store leftovers in an airtight container in the fridge for up to three days.

Flavor Variations

For extra richness, add grated cheddar or Gruyère cheese into the sauce. Swap mushrooms for chopped bell peppers or add toasted nuts for crunch.

Warm and creamy Old-School Green Bean Casserole, perfect for holiday feasts and gatherings. Save
Warm and creamy Old-School Green Bean Casserole, perfect for holiday feasts and gatherings. | crumbnest.com

This classic casserole guarantees comfort and nostalgia at any holiday table. Enjoy every creamy, crunchy bite!

Recipe FAQ

Can I use frozen green beans?

Yes, thawed and drained frozen green beans work well and save prep time.

How do I make the sauce richer?

Add grated cheddar or Gruyère cheese to the sauce for extra flavor and creaminess.

Can I make this ahead of time?

Assemble in advance and refrigerate; add crispy onions and bake before serving for best texture.

What type of mushrooms should I use?

Cremini or button mushrooms both offer a savory depth to the casserole's flavor.

Is this dish vegetarian?

Yes, when made with vegetable broth and checked fried onion ingredients, it is suitable for vegetarians.

Are there common allergens in this dish?

Contains dairy and gluten; check fried onions and broth labels for possible soy or additional allergens.

Old-School Green Bean Casserole

Tender green beans, mushrooms, creamy sauce, and crispy onions for a nostalgic, crowd-pleasing holiday side.

Prep duration
15 min
Cook duration
35 min
Complete duration
50 min
Created by Chloe Martin


Skill Level Easy

Heritage American

Output 6 Portions

Dietary considerations Meat-Free

Components

Vegetables

01 2 lb fresh green beans, trimmed and cut into 2-inch pieces (or substitute with 2 lb frozen cut green beans, thawed and drained)

Sauce Base

01 2 tablespoons unsalted butter
02 9 oz cremini or button mushrooms, sliced
03 1 small yellow onion, finely chopped
04 2 garlic cloves, minced
05 2 tablespoons all-purpose flour
06 1 cup whole milk
07 1/2 cup heavy cream
08 1/2 cup low-sodium vegetable broth
09 1 teaspoon salt
10 1/2 teaspoon black pepper
11 1/2 teaspoon ground nutmeg (optional)

Topping

01 1 1/2 cups crispy fried onions (store-bought or homemade)

Directions

Phase 01

Preheat Oven: Set oven temperature to 350°F and allow to fully preheat.

Phase 02

Blanch Green Beans: Boil a large pot of salted water. Add green beans and cook for 5 minutes until just tender yet still vibrant. Drain, rinse immediately under cold water to halt cooking, and set aside.

Phase 03

Sauté Aromatics: Melt butter in a large skillet over medium heat. Add mushrooms, cooking for 5–6 minutes until softened and lightly browned. Stir in onion and garlic and sauté 2–3 minutes until translucent.

Phase 04

Prepare Cream Sauce: Sprinkle flour over vegetables, stirring for 1 minute to cook out raw flavor. Pour in milk, cream, and broth gradually, whisking constantly. Simmer for approximately 5 minutes until gently thickened. Season with salt, pepper, and nutmeg if desired.

Phase 05

Combine Beans and Sauce: Add drained green beans to skillet and fold into sauce, ensuring even coating.

Phase 06

Layer and Top: Transfer mixture to a 2-quart baking dish. Evenly distribute half of the crispy fried onions atop the surface.

Phase 07

Initial Baking: Bake for 25 minutes until filling is bubbling.

Phase 08

Finish with Remaining Onions: Remove dish from oven. Sprinkle remaining fried onions over casserole and return to oven for 5–7 minutes until topping is golden and crisp.

Phase 09

Rest and Serve: Cool dish for 5 minutes prior to serving for improved structure.

Tools needed

  • Large pot
  • Colander
  • Large skillet
  • Whisk
  • 2-quart baking dish
  • Oven

Allergy details

Review each component for potential allergens and seek medical guidance if you're uncertain about ingredients.
  • Contains dairy (milk, cream, butter), wheat (flour, crispy fried onions), and possible soy in store-bought onions. Confirm specific product labels for additional allergens.

Nutritional information (each portion)

These values are approximate guides only and shouldn't replace professional medical consultation.
  • Energy: 265
  • Fats: 15 g
  • Carbohydrates: 25 g
  • Proteins: 6 g