Old School Green Bean Casserole

Featured in: Home Comforts

This comforting dish combines tender green beans with a rich, creamy sauce made from sautéed mushrooms, onions, garlic, and a blend of milk and cream. The mixture is baked until bubbly and finished with a crunchy layer of golden fried onions. Ideal for festive dinners, it pairs beautifully with roasted poultry and adds nostalgic flair to any meal.

Updated on Thu, 13 Nov 2025 12:19:00 GMT
Creamy, bubbling Old-School Green Bean Casserole topped with golden, crunchy fried onions, ready to serve. Save
Creamy, bubbling Old-School Green Bean Casserole topped with golden, crunchy fried onions, ready to serve. | snacksplat.com

Old-School Green Bean Casserole is a nostalgic, creamy side dish featuring tender green beans, savory mushrooms, and crispy fried onions. This classic is beloved at holiday feasts and family dinners.

I remember my grandmother making this casserole every Thanksgiving. The aromas of butter and onion wafting from the oven always meant family was close, and the crispy topping was everyone's favorite part.

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: ½ tsp (optional)
  • Crispy fried onions: 150 g (1½ cups), store-bought or homemade

Instructions

Preheat oven:
Set oven temperature to 180°C (350°F).
Prep 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 rinse under cold water. Set aside.
Cook vegetables:
In a large skillet on medium heat, melt butter. Add mushrooms and cook for 5-6 minutes till tender and browned. Add onion and garlic, cook 2-3 minutes more till softened.
Make the sauce:
Stir in flour and cook for 1 minute, stirring. Gradually whisk in milk, cream, and broth. Simmer until thickened, around 5 minutes. Season with salt, pepper, and nutmeg if using.
Combine:
Add drained green beans to the skillet and mix to coat in sauce.
Bake first time:
Transfer mixture to a 2-liter (2-quart) baking dish. Top with half the crispy fried onions.
Bake second time:
Bake for 25 minutes until bubbling. Add remaining onions and bake another 5-7 minutes until crisp and golden.
Serve:
Let cool for 5 minutes before serving.
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This casserole brought everyone together at our family table, with each person vying for the crispiest onions on top. It's a tradition that's still requested every year.

Required Tools

Large pot, colander, large skillet, whisk, 2-liter (2-quart) baking dish, oven

Allergen Information

Contains milk (dairy), wheat (in flour and fried onions), and possibly soy (check fried onions and broth labels)

Nutrition

Per serving: 265 calories, 15 g total fat, 25 g carbohydrates, 6 g protein

A warm baking dish filled with homemade Old-School Green Bean Casserole, a classic comfort food. Save
A warm baking dish filled with homemade Old-School Green Bean Casserole, a classic comfort food. | snacksplat.com

Serve this old-school favorite piping hot, and watch it disappear from the table. For leftovers, gently reheat in the oven to retain the crispy topping.

Recipe Guide

Can frozen green beans be used instead of fresh?

Yes, thawed and drained frozen green beans work well, maintaining texture while saving prep time.

How can I make the sauce thicker?

Simmer the sauce longer to reduce liquid, or add a bit more flour when sautéing to increase thickness.

Are crispy fried onions necessary for topping?

They add signature crunch and flavor, but toasted breadcrumbs or nuts can be used as alternatives.

What variations can enhance the dish?

Adding grated sharp cheddar or Gruyère cheese to the sauce boosts richness and depth of flavor.

Can this dish be prepared ahead of time?

Yes, assemble the casserole before baking, refrigerate up to 24 hours, then add onions and bake when ready.

Old School Green Bean Casserole

Tender green beans in a creamy mushroom sauce topped with crispy fried onions, perfect for holiday sides.

Prep duration
15 min
Kitchen time
35 min
Complete duration
50 min
Created by Katie Miller


Skill level Easy

Heritage American

Output 6 Portions

Nutrition Labels Meat-free

What you'll need

Vegetables

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

Sauce Base

01 2 tbsp unsalted butter
02 9 oz cremini or button mushrooms, sliced
03 1 small yellow onion, finely chopped
04 2 garlic cloves, minced
05 2 tbsp all-purpose flour
06 1 cup whole milk
07 ½ cup heavy cream
08 ½ cup low-sodium vegetable broth
09 1 tsp salt
10 ½ tsp black pepper
11 ½ tsp ground nutmeg (optional)

Topping

01 1½ cups crispy fried onions (store-bought or homemade)

Method

Step 01

Preheat oven: Set the oven to 350°F (180°C) to heat while preparing the ingredients.

Step 02

Blanch green beans: Bring a large pot of salted water to a boil. Add green beans and cook for 5 minutes until just tender and bright green. Drain and immediately rinse under cold water to halt cooking. Set aside.

Step 03

Sauté mushrooms, onion, and garlic: In a large skillet over medium heat, melt butter. Add mushrooms and cook 5–6 minutes until browned and tender. Stir in onion and garlic; cook an additional 2–3 minutes until softened.

Step 04

Prepare sauce: Sprinkle flour over the sautéed vegetables and cook, stirring constantly, for 1 minute. Slowly whisk in milk, cream, and vegetable broth. Bring mixture to a simmer and cook until thickened, about 5 minutes. Season with salt, black pepper, and nutmeg if using.

Step 05

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

Step 06

Assemble casserole: Transfer the green bean mixture into a 2-quart baking dish. Evenly sprinkle half of the crispy fried onions over the top.

Step 07

First bake: Bake in the preheated oven for 25 minutes until the casserole is bubbling.

Step 08

Add remaining topping and finish baking: Remove from oven, sprinkle remaining fried onions on top, and bake for an additional 5–7 minutes until the onions are golden and crisp.

Step 09

Rest before serving: Allow the dish to rest for 5 minutes before serving to let flavors meld.

Kitchen tools

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

Allergy details

Always review ingredients for potential allergens and seek professional medical guidance if uncertain.
  • Contains milk (dairy), wheat (gluten in flour and fried onions), and potentially soy (in store-bought fried onions). Verify labels for allergens.

Nutrient breakdown (each portion)

Numbers shown are estimates only - please consult healthcare providers for specific advice.
  • Energy: 265
  • Fats: 15 g
  • Carbohydrates: 25 g
  • Proteins: 6 g