Mushroom Green Bean Casserole

Alright, let me tell you—this Mushroom Green Bean Casserole is my go-to side dish when I want to impress guests without breaking a sweat. Imagine crispy green beans tossed with tender mushrooms and smothered in a creamy, dreamy sauce that’s bursting with umami goodness. The best part? Those golden, crunchy fried onions on top that add just the right amount of salty crunch. It’s comfort food with a bit of a gourmet twist, and once you make it, you’ll understand why it’s a kitchen favorite. Plus, there are some easy tricks to keep your casserole from getting soggy and bland—trust me, I’ve messed this up enough to share the best fixes!

Quick Facts

• Yield: Serves 6
• Prep Time: 15 minutes
• Cook Time: 25 minutes
• Total Time: 40 minutes

Ingredients

For the Main Dish:

• 1 lb fresh green beans, trimmed and halved
• 8 oz mushrooms (cremini or white button), sliced
• 1 small yellow onion, finely chopped
• 3 cloves garlic, minced
• 2 tbsp unsalted butter
• 2 tbsp all-purpose flour
• 1 cup chicken broth (or vegetable broth for vegetarian)
• 1 cup half-and-half or whole milk
• 1 tsp soy sauce (adds depth but optional)
• Salt and freshly ground black pepper, to taste
• 1 ½ cups crispy fried onions (store-bought or homemade)

How I Make It

Step 1:

Start by blanching the green beans in boiling salted water for about 3-4 minutes until they’re bright green and slightly tender. Then, drain and plunge them into ice water to stop the cooking—this keeps the beans crisp and vibrant.

Step 2:

Meanwhile, melt butter in a large skillet over medium heat. Add the chopped onion and sauté until soft and translucent, about 5 minutes. Toss in the mushrooms and cook until they release their moisture and turn golden brown, roughly 7 minutes. Stir in the garlic for the last minute.

Step 3:

Sprinkle the flour over the mushroom mixture and stir constantly for 1-2 minutes to cook out the raw taste. Gradually whisk in the broth and half-and-half, making sure to break up any lumps. Add the soy sauce, and simmer until the sauce thickens—about 3-5 minutes.

Step 4:

Season the sauce with salt and pepper, then fold in the blanched green beans until everything is nicely coated.

Step 5:

Transfer the mixture to a greased 9×13 inch baking dish. Sprinkle the crispy fried onions evenly on top.

Step 6:

Bake in a preheated 350°F oven for 20 minutes, until bubbling and golden on top. Let it rest for 5 minutes before serving to set.

Variations & Tips

• Use fresh green beans for the best texture, but frozen can work in a pinch—just thaw and dry well.
• Swap the fried onions with crispy breadcrumbs mixed with Parmesan for a different crunch.
• Add a splash of white wine to the sauce for an extra flavor boost.
• To make it vegan, use plant-based milk, vegetable broth, and dairy-free butter with crispy fried onions marked vegan.
• For a richer taste, stir in a handful of shredded sharp cheddar before baking.

How I Like to Serve It

This casserole pairs beautifully with roast chicken or turkey during holiday dinners—its creamy texture complements the juicy meats perfectly. On a cozy weeknight, I like it alongside a simple baked salmon and some crusty bread. It’s also a fantastic potluck contribution; everyone loves that crunchy onion topping!

Notes

• Store leftovers covered in the fridge for up to 3 days. Reheat covered at 350°F until warmed through.
• If the sauce seems too thick after baking, stir in a splash of broth or milk before reheating.

Closing: Once you’ve tasted this Mushroom Green Bean Casserole, you’ll see why its creamy richness and crispy topping always steal the show at my table.

Lina

Hi, I’m Lina, the creator of Lina Easy Recipes.Cooking has always been my passion, and I love sharing simple, homemade dishes that anyone can prepare.