Old-School Green Bean Casserole

Featured in: Creamy Comfort Dishes

This comforting side dish blends tender green beans with a creamy mushroom sauce and a crispy fried onion topping. Fresh or frozen beans are gently cooked to preserve their bright color and texture. The savory sauce combines butter, sautéed mushrooms, onion, garlic, and a touch of nutmeg for warmth. Once combined, the mixture is baked until bubbly and topped with golden, crunchy onions for contrast. Ideal for holiday tables or everyday meals alongside poultry.

Updated on Sat, 15 Nov 2025 16:44:00 GMT
Classic Old-School Green Bean Casserole, a creamy, comforting side with crispy onion topping. Pin It
Classic Old-School Green Bean Casserole, a creamy, comforting side with crispy onion topping. | lushkettle.com

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

This casserole reminds me of family Thanksgivings where the aroma of crispy onions filled the house. Every year, it's the first dish emptied at our table—everyone asks for seconds.

Ingredients

  • Fresh green beans: 900 g (2 lb), trimmed and cut into 5 cm (2-inch) pieces (or use frozen, 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

Prepare oven:
Preheat oven to 180°C (350°F).
Cook green beans:
Bring 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.
Make sauce:
In large skillet over medium heat, melt butter. Add mushrooms and cook for 5-6 minutes until tender and browned. Add onion and garlic, cooking for 2-3 minutes until softened.
Add thickener:
Stir in flour and cook for 1 minute, stirring constantly.
Simmer sauce:
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 green beans:
Add drained green beans to skillet and toss to coat in sauce.
Layer casserole:
Transfer mixture to 2-liter (2-quart) baking dish. Sprinkle half of crispy fried onions on top.
Bake:
Bake for 25 minutes until bubbling. Remove, top with remaining onions, and bake for 5-7 minutes until golden and crisp.
Cool:
Let cool for 5 minutes before serving.
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My grandmother always insisted I be the one to sprinkle the crispy onions—a job I took seriously! It's now my own kids' favorite tradition.

Serving Suggestions

Serve alongside roast turkey or chicken. This casserole pairs perfectly with stuffing, mashed potatoes, or savory gravy.

Make Ahead Tips

Assemble up to the onion topping and refrigerate for 24 hours. Add crispy onions just before baking for best texture.

Nutritional Information

Each serving has about 265 calories, 15 g fat, 25 g carbs, and 6 g protein—making it satisfying yet not too heavy.

Golden-brown Old-School Green Bean Casserole bubbling in a baking dish, ready to serve with family. Pin It
Golden-brown Old-School Green Bean Casserole bubbling in a baking dish, ready to serve with family. | lushkettle.com

This timeless casserole is sure to bring smiles and nostalgia to your next feast. Prep it ahead and enjoy every creamy, crispy bite!

Recipe Questions & Answers

Can frozen green beans be used instead of fresh?

Yes, frozen cut green beans can be thawed, drained, and used. They maintain texture well after brief cooking.

What mushrooms work best for the sauce base?

Cremini or button mushrooms are ideal for a rich, earthy flavor and tender texture when sautéed.

How is the creamy sauce thickened?

Flour is cooked with butter and vegetables, then combined with milk, cream, and vegetable broth, simmered until it thickens into a velvety sauce.

Can the dish be prepared ahead of time?

Yes, assemble through baking dish filling, refrigerate up to 24 hours, then add fried onions and bake before serving.

What adds the crispy texture on top?

Crispy fried onions, either store-bought or homemade, are sprinkled on top before baking to add a crunchy finish.

Are there options to enhance flavor?

Adding grated sharp cheddar or Gruyère cheese to the sauce enriches taste and adds depth.

Old-School Green Bean Casserole

Nostalgic creamy side with green beans, mushrooms, and crispy onions, perfect for festive family dinners.

Time to Prep
15 mins
Time to Cook
35 mins
Full Prep Time
50 mins
Created By Samantha Reeves


Skill Level Easy

Culinary Tradition American

Portion 6 Serving Size

Dietary Details Meat-Free

What You Need

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)

Steps

Step 01

Preheat Oven: Set the oven temperature to 350°F to prepare for baking.

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 rinse with cold water to halt cooking. Set aside.

Step 03

Cook Vegetables: Melt butter in a large skillet over medium heat. Add mushrooms and cook for 5 to 6 minutes until browned and tender. Incorporate onion and garlic, cooking 2 to 3 minutes until softened.

Step 04

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

Step 05

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

Step 06

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

Step 07

Bake and Add Topping: Bake for 25 minutes until bubbling. Remove from oven, add remaining fried onions, then bake for an additional 5 to 7 minutes until golden and crisp.

Step 08

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

Tools You'll Need

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

Allergy Info

Review every ingredient for allergens and reach out to your doctor with concerns.
  • Contains milk (dairy), wheat (gluten from flour and fried onions), and possibly soy (in store-bought fried onions). Check ingredient labels carefully.

Nutrition Info (per portion)

Details offered for informational purposes, not as a substitute for professional health guidance.
  • Calories: 265
  • Fats: 15 g
  • Carbohydrates: 25 g
  • Proteins: 6 g