Caramelized Onion Green Bean Casserole

5 from 1 vote

Caramelized Onion Green Bean Casserole

This caramelized onion green bean casserole is perfect for Thanksgiving and Christmas gatherings. It uses fresh green beans and can be made ahead of time, making it a simple and delicious comfort food recipe.

Prep Time1

Cook Time30

Total Time1 30

Course: Sides + Condiments

Cuisine: American

Servings: servings

Calories: 345kcal

Author: Rebecca Warfield

Equipment

Skillet
9x9 Baking Dish

Ingredients

Caramelized Onions

4 tablespoons unsalted butter
1 large onion chopped
8 ounces sliced mushrooms optional

Green Beans

1 ½ pounds fresh green beans ends trimmed and halved

Cream Sauce

4 tablespoons unsalted butter
4 tablespoons all-purpose flour
1 cup chicken broth
1 tablespoon Worcestershire sauce
1 ½ cups milk

Topping

2 cups fried onions such as French's

Instructions

Start the Onions. In a large skillet, melt the butter over medium heat. Add the onions and a pinch of salt. Cook for about 3 minutes or until the onions are translucent.
4 tablespoons unsalted butter, 1 large onion, 8 ounces sliced mushrooms
Caramelize the Onions. Reduce the heat to low, cover the onions and let them cook low and slow until they are a golden color. Stir occasionally.
The secret to caramelized onions is low and slow, so don't rush. This can take 30-45 minutes.
Add Optional Mushrooms. When the onions are 5-10 minutes from done, add the mushrooms if you prefer.
Boil Water and Finish the Onions. While you wait for the onions to finish, bring a large pot of water to a boil.
Then, once the onions are done, transfer them to a separate dish and set aside. Don't wipe out the skillet. Those browned bits will add flavor to the sauce.
Blanch the Green Beans. Add the green beans to the boiling water. Cook for 5-6 minutes or until bright green and slightly tender. Drain and rinse with cool water to stop the cooking process. Set aside.
1 ½ pounds fresh green beans
Preheat the oven. Preheat the oven to 350°F.
Make the Roux. In the same skillet you used to cook the onions, melt the butter over medium heat. Stir in the flour and cook for 1–2 minutes to remove the raw flour taste.
4 tablespoons unsalted butter, 4 tablespoons all-purpose flour
Add the Broth. Pour in the chicken broth and Worcestershire sauce, whisking until the sauce thickens.
1 cup chicken broth, 1 tablespoon Worcestershire sauce
Add the Milk. Add the milk and whisk until smooth and creamy. Season with salt and pepper to taste.
1 ½ cups milk
Combine Caramelized Onions and Sauce. Remove from heat and stir in the caramelized onions.
Mix in the Green Beans. Add the green beans to the sauce and toss until coated.
Assemble the Casserole. Transfer the mixture to a 9x9-inch baking dish and spread evenly. Bake for 25 minutes, or until hot and bubbly.
Add the Topping. Remove from the oven, stir the casserole. Bump up the heat to 375° F. Then, sprinkle with fried onions and bake for an additional 5-10 minutes, until golden and crisp on top and bubbly around the sides of the dish. The flavor will develop as the dish cools, and I even prefer it the next day!
2 cups fried onions

Notes

Taste the sauce as you go, and season with salt and pepper to your liking.
I wrote the instructions so you can overlap steps and save time in the kitchen. However, you can always make each part—onions, beans, and sauce—separately if that works better for you.
I skip the mushrooms because I famously dislike them (right up there with wasabi). But if you love mushrooms in green bean casserole, add them!
Don't rush the onions. Cooking low and slow yields the best caramelized flavor.
To save time, you can make the caramelized onions the day before.
Casseroles often taste better the next day. For busy holidays, make the green bean casserole the day before.

Nutrition