If you are on the lookout for a dish that hugs you with warmth and a burst of comforting flavors, the Creamy Green Bean Mushroom Casserole Recipe is your next kitchen adventure. This recipe merges tender green beans and earthy baby bella mushrooms in a luxuriously creamy sauce, topped with a delightfully crispy layer of fried onions. It’s a perfect blend of textures and tastes that’s as pleasing to the eye as it is to the palate. Whether it’s a holiday table centerpiece or a cozy family dinner, this casserole brings a satisfying, homemade charm that everyone will adore.

Ingredients You’ll Need

The image shows a white plate filled with bright green beans that have a fresh, slightly shiny texture on the right side. To the left, there is a white plate piled with sliced light brown mushrooms with visible gills. Surrounding these main plates are small containers of ingredients: at the top center, a small glass bowl of light golden broth and a glass measuring cup filled with white milk; below these are a small bowl of white flour, a small dish with black pepper and salt, and a small white dish with finely chopped garlic. At the bottom left, there is a small white dish with a stick of pale yellow butter, a small white bowl with dark soy sauce, and a small wooden bowl filled with crispy fried onions. All items are set on a white marbled surface. Photo taken with an iphone --ar 4:5 --v 7

Gathering simple, quality ingredients is the secret to the success of this tasty casserole. Each one plays a crucial role in building the perfect balance of creaminess, savor, and texture that makes this dish unforgettable.

Salted butter (¼ cup): Adds rich flavor and a velvety base for your sauce as it melts.
Baby bella mushrooms (24 ounces): These mushrooms bring a hearty, earthy depth and a meaty texture.
Garlic (1 tablespoon minced): The aromatic kick that wakes up your taste buds and blends beautifully with mushrooms.
All-purpose flour (2.5 tablespoons): The magic thickener that transforms liquids into a luscious, creamy sauce.
2% milk (¾ to 1 cup): Provides the creamy consistency that makes this casserole so irresistible without being too heavy.
Low sodium chicken broth (½ cup): Adds subtle savory notes and a touch of moisture to keep everything perfectly tender.
Low sodium soy sauce (1.5 tablespoons): A dash of umami that deepens the flavor without overpowering the freshness of the green beans.
Fresh green beans (24 ounces): Crisp, vibrant, and full of color—they bring life and crunch to the dish.
Kosher salt and black pepper: Essential for seasoning and rounding out all the flavors harmoniously.
Crispy fried onions (½ cup): The crowning glory that adds crunch and a little golden crispiness on top.

How to Make Creamy Green Bean Mushroom Casserole Recipe

Step 1: Sauté the Mushrooms and Garlic

Start by preheating your oven to 350 degrees. Grab a large, oven-safe pan and heat it over medium-high. Melt the butter, then add your sliced baby bella mushrooms and minced garlic. Cook until the mushrooms soften and release their juices, then brown lightly. This step develops deep, rich flavors and draws out the mushroom’s natural umami.

Step 2: Create the Creamy Base

Once the mushrooms have browned, sprinkle the all-purpose flour along with kosher salt and black pepper. Stir well as the flour absorbs the moisture. Then reduce the heat to medium and slowly add the milk, stirring constantly. This is when the magic happens—the sauce thickens and becomes silky-smooth. Finish by whisking in the chicken broth, adding more if the sauce seems too thick, creating that perfect creamy coating.

Step 3: Add the Flavor Boosters

Next, pour in the low sodium soy sauce and stir. This adds an extra layer of savory depth to the casserole, enhancing all the other flavors with a subtle richness. Your sauce should now be velvety and well-seasoned, ready to marry with the fresh green beans.

Step 4: Simmer the Green Beans

Add the fresh green beans directly to the pan. If you prefer a slight crunch, add them straight away and simmer gently for about 10 minutes. If you like them a bit softer, blanch them first in boiling water for a few minutes, then simmer for about 5 minutes. This step ensures the beans absorb the sauce’s flavors without losing their vibrant color or getting mushy.

Step 5: Prepare for Baking and Add Topping

If you like, transfer the mixture to a lightly greased 9×13-inch baking dish for even baking and easier serving. Sprinkle the crispy fried onions generously on top, then cover with foil. Bake for 20 minutes, then uncover and bake for another 5 minutes to get the onions golden and crunchy. This final step gives the casserole a fantastic texture contrast that guests will rave about.

How to Serve Creamy Green Bean Mushroom Casserole Recipe

The dish on a white plate shows three main layers: at the bottom, bright green long green beans laid out flat; in the middle layer, brown sautéed sliced mushrooms scattered over the beans; on top, a sprinkling of golden crispy fried onions. The dish is covered lightly with a glossy, tan mushroom sauce that adds shine and small pools around the edges. A gold fork rests on the bottom left side of the plate, partially touching the green beans. The plate is placed on a white marbled surface, with a soft green cloth with frayed edges to the right and a glass with light amber liquid in the bottom left corner. Photo taken with an iphone --ar 4:5 --v 7

Garnishes

Adding a sprinkle of fresh chopped parsley or a light dusting of freshly grated Parmesan can elevate your casserole’s appearance and flavor. These fresh touches bring a pop of color and a subtle brightness that balances out the creamy richness.

Side Dishes

This casserole pairs wonderfully with roasted meats like turkey, chicken, or pork, making it a hero at holiday meals. It is equally delicious alongside a crisp salad or buttery mashed potatoes, creating a meal full of complementary textures and flavors that satisfy every craving.

Creative Ways to Present

For a charming presentation, serve individual portions in ramekins topped with extra fried onions right before serving. Alternatively, add a layer of shredded cheese beneath the onions before baking for a melty surprise. The creamy green bean mushroom casserole recipe shines in any presentation, making it both a comfort food and a showstopper.

Make Ahead and Storage

Storing Leftovers

After enjoying your meal, store any leftover casserole in an airtight container in the refrigerator. It will keep well for 3 to 4 days. The flavors meld beautifully overnight, so leftovers taste even better the next day.

Freezing

You can freeze this casserole for up to 2 months. For freezing, prepare the casserole up to the baking step, then cool completely before wrapping tightly with foil and plastic wrap. When you’re ready, thaw overnight in the fridge before baking as directed.

Reheating

Reheat in the oven at 350 degrees until warmed through, about 15 to 20 minutes. Cover with foil to prevent drying out. Alternatively, microwave individual servings on medium power, stirring occasionally to heat evenly, though the oven method retains the best texture.

FAQs

Can I use canned green beans instead of fresh?

Fresh green beans are preferred for their crisp texture and vibrant flavor, but if you use canned, drain them thoroughly and reduce simmering time since they are already cooked.

Is there a vegetarian version of the Creamy Green Bean Mushroom Casserole Recipe?

Absolutely! Substitute the chicken broth with vegetable broth to keep it vegetarian without sacrificing any of the savory goodness.

Can I make this casserole dairy-free?

Yes, you can swap the butter for a dairy-free alternative and use plant-based milk such as almond or oat milk. Just ensure the milk is unsweetened and unflavored for best results.

What’s the best way to achieve crispy fried onions?

For extra crispiness, sprinkle the fried onions on just before serving or bake a little longer uncovered. Alternatively, you can toast them lightly in a dry skillet before adding to the casserole.

Can I prepare this casserole in advance for a holiday meal?

Definitely! Prepare it up to the baking step, refrigerate overnight, then bake right before serving for fresh, hot comfort that complements any festive spread.

Final Thoughts

This Creamy Green Bean Mushroom Casserole Recipe combines simplicity with indulgence in the best possible way. It’s a dish that feels like a warm hug, celebrates earthy flavors, and adds a bit of magic to any meal. Once you try it, you’ll understand why it’s become a treasured favorite. So gather your ingredients, invite your loved ones, and create a delicious memory with every bite.