Old-School Green Bean Casserole

Featured in: Comfort Food Cravings

This comforting dish brings together tender green beans and savory mushrooms in a creamy sauce, topped with crispy fried onions. The green beans are gently cooked to retain their bright color and texture before being combined with a rich sauce made from butter, mushrooms, onion, garlic, milk, cream, and broth. Baked until bubbling and golden, the crispy onions add a delightful crunch. Perfect for family gatherings and holiday meals, this timeless side balances creamy and crispy textures harmoniously.

Updated on Sat, 15 Nov 2025 14:51:00 GMT
Golden, bubbly Old-School Green Bean Casserole with a creamy mushroom sauce and crispy onions. Save
Golden, bubbly Old-School Green Bean Casserole with a creamy mushroom sauce and crispy onions. | toastytongs.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 made green bean casserole for our Thanksgiving potluck and it instantly became a family favorite. My grandmother always requested extra crispy onions on top, and now it is a must-have at every festive gathering.

Ingredients

  • Fresh green beans: 900 g (2 lb), trimmed and cut into 5 cm (2-inch) pieces (or 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 (½ cup)
  • Low-sodium vegetable broth: 120 ml (½ cup)
  • Salt: 1 tsp
  • Black pepper: ½ tsp
  • Ground nutmeg (optional): ½ tsp
  • Crispy fried onions: 150 g (1½ cups), store-bought or homemade

Instructions

Prep oven and beans:
Preheat oven to 180°C (350°F). Bring a large pot of salted water to a boil. Add green beans and cook for 5 minutes until just tender and still bright green. Drain and rinse under cold water. Set aside.
Make sauce:
Melt butter in a large skillet over medium heat. Add mushrooms and cook for 5-6 minutes until tender and browned. Add onion and garlic, cook for 2-3 minutes until softened.
Thicken sauce:
Stir in flour and cook for 1 minute, stirring constantly. Gradually whisk in milk, cream, and broth. Simmer until thickened, about 5 minutes. Season with salt, pepper, and nutmeg (if using).
Combine beans and sauce:
Add drained green beans and toss to coat evenly in sauce.
Assemble and bake:
Transfer mixture to a 2-liter (2-quart) baking dish. Sprinkle half the crispy fried onions on top.
Bake and finish:
Bake for 25 minutes until bubbling. Top with remaining onions and bake 5-7 minutes more until golden and crisp.
Rest and serve:
Let cool for 5 minutes before serving.
A warm, comforting image of classic Old-School Green Bean Casserole ready to be scooped and enjoyed. Save
A warm, comforting image of classic Old-School Green Bean Casserole ready to be scooped and enjoyed. | toastytongs.com

Our kids love helping sprinkle the crispy onions on top after school, turning this simple dish into a fun family tradition.

Make Ahead & Storage

Assemble the casserole through the sauce and bean step and refrigerate for up to 24 hours. Add crispy onions and bake when ready to serve. Store leftovers in an airtight container in the fridge for up to 3 days.

Customization Tips

Try mixing in a handful of grated sharp cheddar or Gruyère cheese for a richer flavor, or substitute button mushrooms with shiitake for a gourmet twist.

Serving Suggestions

Green bean casserole pairs beautifully with roast turkey, chicken, or ham, and makes a delightful vegetarian side for any holiday meal.

Tender green beans are coated in sauce and topped with crispy onions in this Old-School Green Bean Casserole. Save
Tender green beans are coated in sauce and topped with crispy onions in this Old-School Green Bean Casserole. | toastytongs.com

This old-school casserole brings warmth and nostalgia to the table, with every bite recalling cozy gatherings with family and friends.

Recipe FAQ

Can fresh green beans be substituted with frozen?

Yes, frozen cut green beans can be used but should be thoroughly thawed and drained to avoid excess moisture in the dish.

How can I make the sauce thicker?

Cooking the flour with butter before gradually whisking in the liquids helps create a thick, creamy sauce that coats the beans evenly.

What is the best way to get crispy fried onions on top?

Using store-bought crispy fried onions or making them at home ensures a crunchy topping. Add half before baking and the rest near the end for extra crispness.

Can I prepare this dish ahead of time?

Yes, assemble through step 6, refrigerate up to 24 hours, then add the topping and bake before serving.

What flavors complement this green bean side?

Adding sharp cheddar or Gruyère cheese to the sauce enhances depth, and it pairs well with roasted turkey or chicken.

Old-School Green Bean Casserole

Nostalgic creamy side with tender green beans, savory mushrooms, and crispy fried onions for a comforting dish.

Prep duration
15 min
Cook duration
35 min
Complete duration
50 min
Created By Daniel Brooks


Skill Level Easy

Heritage American

Output 6 Portions

Dietary considerations Meat-Free

Components

Vegetables

01 2 pounds fresh green beans, trimmed and cut into 2-inch pieces, or frozen cut green beans thawed and drained

Sauce Base

01 2 tablespoons unsalted butter
02 9 ounces 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.

Phase 02

Blanch Green Beans: Bring a large pot of salted water to a boil, add green beans, and cook for 5 minutes until tender-crisp. Drain and rinse under cold water to stop cooking; set aside.

Phase 03

Sauté Vegetables: Melt butter in a large skillet over medium heat. Add mushrooms and cook 5-6 minutes until browned. Add onion and garlic; sauté 2-3 minutes until softened.

Phase 04

Create Sauce: Stir in flour and cook for 1 minute while stirring. Gradually whisk in milk, cream, and vegetable broth. Simmer until thickened, about 5 minutes. Season with salt, pepper, and nutmeg if using.

Phase 05

Combine Beans and Sauce: Add the drained green beans to the skillet and toss to coat evenly with the sauce.

Phase 06

Prepare for Baking: Transfer the mixture to a 2-quart baking dish. Sprinkle half of the crispy fried onions evenly over the top.

Phase 07

Bake First Layer: Bake uncovered for 25 minutes until bubbling.

Phase 08

Add Final Topping and Bake: Remove from oven, add remaining fried onions, then bake an additional 5-7 minutes until topping is golden and crisp.

Phase 09

Rest Before Serving: Allow to cool for 5 minutes before serving.

Tools needed

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

Allergy details

Review each ingredient for potential allergens and consult with a healthcare professional if you're uncertain.
  • Contains dairy, gluten (in flour and fried onions), and possibly soy in store-bought fried onions.

Nutritional information (per portion)

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