Old-School Green Bean Casserole

Featured in: Crispy Crunch Fix

This nostalgic side features tender green beans coated in a savory mushroom cream sauce, baked to perfection with a crispy fried onion topping. The dish balances fresh vegetables with rich dairy, making it a beloved choice for family dinners and holiday meals. Preparation involves blanching green beans, simmering mushrooms and aromatics in a creamy base, then baking everything until bubbly and golden. Optional sharp cheese can enrich the sauce, adding bold flavor. Serve warm alongside roasted poultry or your preferred mains for a classic, satisfying accompaniment.

Updated on Thu, 13 Nov 2025 10:11:00 GMT
Creamy, classic Old-School Green Bean Casserole with golden crispy onions, perfect for a cozy Thanksgiving. Save
Creamy, classic Old-School Green Bean Casserole with golden crispy onions, perfect for a cozy Thanksgiving. | whambite.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 have fond memories of making this casserole for every Thanksgiving and it always brings back the feeling of celebration when the aroma fills the kitchen.

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 (1/2 cup)
  • Low-sodium vegetable broth: 120 ml (1/2 cup)
  • Salt: 1 tsp
  • Black pepper: 1/2 tsp
  • Ground nutmeg: 1/2 tsp optional
  • Crispy fried onions: 150 g (1 1/2 cups) store-bought or homemade

Instructions

Prep the oven:
Preheat the oven to 180°C (350°F).
Cook the 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.
Make the 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 2-3 minutes until softened.
Thicken the 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).
Add beans and assemble:
Add drained green beans to skillet and toss to coat. Transfer mixture to a 2-liter (2-quart) baking dish. Sprinkle half the crispy fried onions on top.
Bake and finish:
Bake 25 minutes until bubbling. Remove from oven top with remaining onions and bake 5-7 minutes more until golden and crisp. Let cool for 5 minutes before serving.
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This casserole has always been a staple at our family table even for simple Sunday dinners—everyone waits for the crispy onion topping.

Required Tools

Large pot colander large skillet whisk and a 2-liter (2-quart) baking dish are essential. An oven is required for baking.

Allergen Information

Contains milk wheat (in flour and fried onions) and soy (possibility in store-bought fried onions). Always double-check ingredient labels.

Nutritional Information

Each serving provides about 265 calories 15 g total fat 25 g carbohydrates and 6 g protein.

Homemade Old-School Green Bean Casserole: Tender green beans in a rich sauce, ready to serve with family. Save
Homemade Old-School Green Bean Casserole: Tender green beans in a rich sauce, ready to serve with family. | whambite.com

This old-school green bean casserole is sure to bring back happy memories one delicious bite at a time. It's a must-have for any holiday table.

Kitchen Guide

How do I achieve tender but crisp green beans?

Blanch green beans in boiling salted water for about 5 minutes, then immediately rinse with cold water to stop cooking, preserving their bright color and slight crunch.

Can I use frozen green beans instead of fresh?

Yes, frozen cut green beans that are thawed and drained work well and save prep time without sacrificing texture or flavor.

What mushrooms are best for the sauce base?

Cremini or button mushrooms are ideal for their mild earthy flavor and tender texture when cooked, enhancing the sauce’s richness.

How can I make the topping extra crispy?

Add the fried onions halfway through baking, save some for topping later, and bake until golden to maintain a satisfying crunch.

Is there an option to boost the sauce flavor?

Incorporate 50 g of grated sharp cheddar or Gruyère cheese into the sauce for a richer, more pronounced taste.

Can this dish be prepared ahead of time?

Yes, assemble up to step 6, refrigerate for up to 24 hours, then add onions and bake before serving to save time on busy days.

Old-School Green Bean Casserole

Creamy green beans with mushrooms and crispy onions for a comforting festive dish.

Prep Duration
15 min
Cook Duration
35 min
Complete Duration
50 min
Created by Brandon Ellis


Skill Level Easy

Heritage American

Output 6 Portions

Diet Requirements 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

Phase 01

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

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

Phase 03

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

Phase 04

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

Phase 05

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

Phase 06

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

Phase 07

Bake and add topping: Bake uncovered for 25 minutes until bubbling. Remove from oven, add remaining onions on top, then return and bake 5 to 7 minutes until golden and crisp.

Phase 08

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

Kitchen Tools

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

Allergy Guide

Review ingredients carefully for potential allergens and seek professional medical guidance if unsure
  • Contains milk (dairy), wheat (gluten), and potentially soy in fried onions.

Nutrient Breakdown (per portion)

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