Old-School Green Bean Casserole

Featured in: Comfort Food

This comforting green bean dish layers tender green beans with a savory mushroom sauce, enriched by butter, cream, and subtle spices. Crispy fried onions add a golden, crunchy topping that complements the creamy base. The beans are blanched just right to keep their fresh color and tender bite before being baked to bubbling perfection. Ideal for family dinners or holiday feasts, this classic side offers a nostalgic, hearty flavor loved across generations. Optional sharp cheddar or Gruyère adds depth, while easy prep and baking steps make it accessible for any cook.

Updated on Thu, 13 Nov 2025 13:45:00 GMT
Warm, bubbly Old-School Green Bean Casserole with a crispy fried onion topping, perfect for any holiday table. Save
Warm, bubbly Old-School Green Bean Casserole with a crispy fried onion topping, perfect for any holiday table. | berrycottage.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 remember helping my grandmother layer green beans and those crunchy onions in her old casserole dish every Thanksgiving. The aroma as it baked is still one of my favorite family memories.

Ingredients

  • Vegetables: 900 g (2 lb) fresh green beans, trimmed and cut into 5 cm (2-inch) pieces (or substitute with 900 g frozen cut green beans, thawed and drained)
  • Sauce Base: 2 tbsp unsalted butter, 250 g (9 oz) cremini or button mushrooms, sliced, 1 small yellow onion, finely chopped, 2 garlic cloves, minced, 2 tbsp all-purpose flour, 240 ml (1 cup) whole milk, 120 ml (½ cup) heavy cream, 120 ml (½ cup) low-sodium vegetable broth, 1 tsp salt, ½ tsp black pepper, ½ tsp ground nutmeg (optional)
  • Topping: 150 g (1½ cups) crispy fried onions (store-bought or homemade)

Instructions

Prep Oven & Beans:
Preheat the 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 but still bright green. Drain and immediately rinse under cold water to stop cooking. Set aside.
Cook Veggies & Sauce:
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. 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 & Bake:
Add the drained green beans to the skillet and toss to coat evenly in the sauce. Transfer the mixture to a 2-liter (2-quart) baking dish. Sprinkle half of the crispy fried onions on top. Bake for 25 minutes until bubbling. Remove from oven, top with remaining onions, and bake for 5-7 minutes more until golden and crisp.
Serve:
Let cool for 5 minutes before serving.
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| berrycottage.com

Whenever our extended family gathers, this dish is always scraped clean in minutes. Kids love it as much as the grownups, and there's something special about sharing the tradition across generations.

Required Tools

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

Allergen Information

Contains milk and wheat (gluten), and may contain soy if using store-bought fried onions. Double-check ingredient labels to suit dietary needs.

Nutritional Information

Per serving: Calories 265, Total Fat 15 g, Carbohydrates 25 g, Protein 6 g

A comforting photo of creamy Old-School Green Bean Casserole, showcasing tender green beans in a rich mushroom sauce. Save
A comforting photo of creamy Old-School Green Bean Casserole, showcasing tender green beans in a rich mushroom sauce. | berrycottage.com

This classic side dish will add warmth and nostalgia to any table. Enjoy with friends and family for a truly comforting experience!

Recipe FAQ

How do I keep green beans tender but crisp?

Blanch green beans for about 5 minutes in boiling salted water, then immediately rinse under cold water to stop cooking and preserve their bright color and crisp texture.

Can I use frozen green beans instead of fresh?

Yes, thaw and drain frozen cut green beans before using to ensure excess moisture doesn't affect the sauce consistency.

What mushrooms work best for the sauce?

Cremini or button mushrooms provide a mild yet earthy flavor and develop a nice browned texture when sautéed.

How is the creamy sauce thickened?

A mixture of butter, flour, and dairy (milk and cream) is cooked into a smooth sauce that thickens gently before coating the green beans.

What’s the best way to achieve crispy topping?

Sprinkle fried onions on top midway through baking, then add more for a final 5–7 minute bake until golden and crisp.

Can I prepare this dish ahead of time?

Assemble up to the point before adding fried onions and baking, then refrigerate for up to 24 hours. Add onions and bake just before serving.

Old-School Green Bean Casserole

Creamy green beans paired with mushrooms and crispy onions, perfect for cozy holiday gatherings.

Prep duration
15 min
Cook duration
35 min
Complete duration
50 min
Created by Lily Anderson


Complexity 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 2 lb 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

Directions

Direction 01

Preheat oven: Set the oven to 350°F (180°C).

Direction 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 but still bright green. Drain and rinse under cold water to halt cooking. Set aside.

Direction 03

Sauté vegetables: Melt butter in a large skillet over medium heat. Add mushrooms and cook for 5-6 minutes until browned and tender. Incorporate onion and garlic, cooking for an additional 2-3 minutes until softened.

Direction 04

Prepare sauce: Stir in flour and cook for 1 minute while stirring constantly. Gradually whisk in milk, cream, and vegetable broth. Simmer and cook until the sauce thickens, approximately 5 minutes. Season with salt, pepper, and nutmeg if using.

Direction 05

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

Direction 06

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

Direction 07

Bake with topping: Bake for 25 minutes until the casserole is bubbling. Remove from oven, add the remaining fried onions, and continue baking for another 5-7 minutes until golden and crisp.

Direction 08

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

Necessary tools

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

Allergy information

Review each ingredient for potential allergens and seek professional medical advice if you have concerns.
  • Contains milk (dairy), wheat (gluten in flour and fried onions), and possibly soy (in some fried onions). Verify ingredient labels.

Nutritional information (per portion)

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