Description
This Old-School Green Bean Casserole is a comforting, classic side dish featuring tender green beans in a creamy mushroom sauce topped with crispy fried onions. It combines fresh or thawed green beans sautéed with mushrooms, onions, and garlic in a rich, thickened sauce made from milk, cream, and vegetable broth. Baked until bubbly and golden, this casserole is perfect for holiday meals or cozy family dinners.
Ingredients
Scale
Vegetables
- 2 lb fresh green beans, trimmed and cut into 2-inch pieces or 2 lb frozen cut green beans, thawed and drained
- 9 oz cremini or button mushrooms, sliced
- 1 small yellow onion, finely chopped
- 2 garlic cloves, minced
Dairy & Butter
- 2 tbsp unsalted butter
- 1 cup whole milk
- ½ cup heavy cream
Pantry Items
- 2 tbsp all-purpose flour
- ½ cup low-sodium vegetable broth
- 1 tsp salt
- ½ tsp black pepper
- ½ tsp ground nutmeg (optional)
- 1½ cups crispy fried onions, store-bought or homemade
Instructions
- Preheat oven: Set your oven to 350°F (180°C) so it’s ready for baking the casserole later.
- Blanch green beans: Bring a large pot of salted water to a boil. Add the green beans and cook them for 5 minutes until just tender but still bright green. Drain and rinse under cold water to stop the cooking process. Set aside.
- Sauté vegetables: Melt the butter in a large skillet over medium heat. Add the sliced mushrooms and cook for 5-6 minutes until they become browned and tender. Add the chopped onion and minced garlic, and cook for another 2-3 minutes until softened.
- Prepare sauce: Stir in the flour and cook for 1 minute, stirring constantly. Gradually whisk in the milk, heavy cream, and vegetable broth. Simmer gently and cook until the sauce thickens, about 5 minutes. Season with salt, black pepper, and optional ground nutmeg.
- Combine green beans and sauce: Add the drained green beans to the skillet and toss everything together to coat the beans evenly with the creamy mushroom sauce.
- Assemble casserole: Transfer the green bean and sauce mixture into a 2-quart baking dish. Sprinkle half of the crispy fried onions evenly over the top of the mixture.
- Bake with topping: Place the casserole in the preheated oven and bake for 25 minutes until it is bubbling. Remove from the oven, add the remaining fried onions on top, then return to bake for an additional 5-7 minutes until the onions are golden and crisp.
- Rest before serving: Let the casserole cool for 5 minutes before serving to allow it to set slightly and make serving easier.
Notes
- Fresh green beans provide the best texture, but frozen and thawed green beans work well too.
- For extra flavor, you can use low-sodium chicken broth instead of vegetable broth if not keeping vegetarian.
- If you prefer, make your own crispy fried onions by thinly slicing onions and frying them until golden.
- The nutmeg is optional but adds a nice warm flavor to the creamy sauce.
- This casserole can be prepared a few hours ahead and refrigerated before baking. Just extend the baking time slightly if baking from cold.
- Prep Time: 15 minutes
- Cook Time: 40 minutes
- Category: Side Dish
- Method: Baking
- Cuisine: American
Keywords: green bean casserole, classic casserole, holiday side dish, creamy mushroom sauce, crispy fried onions, vegetarian casserole
