Green Bean and Portabella Casserole

Elevate your holiday table or weeknight dinner with this Green Bean and Portabella Casserole, a gourmet twist on the classic comfort food. Packed with fresh green beans, hearty portabella mushrooms, and a rich, creamy sauce infused with garlic, onions, and fragrant thyme, this casserole delivers bold flavors in every bite. Topped with crispy fried onions and a sprinkle of Parmesan cheese, it balances crunch with velvety decadence. Perfect as a crowd-pleasing side dish or vegetarian main, this recipe is easy to prepare with a blend of familiar ingredients and restaurant-quality taste. Ready in just over an hour, this casserole is a guaranteed hit for gatherings or cozy family meals.

Nutriscore Rating: 62/100

Prep Time:20 mins

Cook Time:40 mins

Total Time:60 mins

Servings: 6

Ingredients

• 1 pound fresh green beans
• 8 ounces portabella mushrooms
• 2 tablespoons olive oil
• 2 tablespoons unsalted butter
• 1 whole medium yellow onion
• 3 whole garlic cloves
• 2 tablespoons all-purpose flour
• 1 cup vegetable broth
• 1 cup heavy cream
• 1 teaspoon fresh thyme leaves
• 1 teaspoon salt
• 0.5 teaspoon black pepper
• 0.5 cup shredded Parmesan cheese
• 1.5 cups crispy fried onions

Directions

Step 1

Preheat your oven to 375°F (190°C).

Step 2

Trim the ends off the green beans and blanch them in boiling water for 3-4 minutes until just tender. Drain and set aside.

Step 3

Clean the portabella mushrooms with a damp paper towel and slice them into thick strips.

Step 4

In a large skillet, heat the olive oil over medium-high heat. Add the mushrooms and cook for 5-6 minutes until they release their moisture and turn golden brown. Remove and set aside.

Step 5

In the same skillet, melt the butter over medium heat. Add the onion, finely diced, and sauté for 3-4 minutes until soft and translucent.

Step 6

Mince the garlic cloves and add them to the skillet. Cook for an additional 30 seconds until fragrant.

Step 7

Sprinkle the flour evenly over the onion mixture and stir well to form a roux. Cook for 1-2 minutes to eliminate the raw flour taste.

Step 8

Gradually whisk in the vegetable broth and heavy cream, ensuring no lumps remain. Bring the mixture to a simmer, stirring frequently until it thickens, about 3-4 minutes.

Step 9

Stir in the thyme, salt, black pepper, and Parmesan cheese until fully incorporated.

Step 10

In a large mixing bowl, combine the blanched green beans, cooked mushrooms, and sauce. Mix well to coat evenly.

Step 11

Transfer the mixture to a greased 9x13-inch baking dish and spread it out evenly.

Step 12

Top the casserole with the crispy fried onions, spreading them in an even layer.

Step 13

Bake in the preheated oven for 20-25 minutes until bubbly and golden brown on top.

Step 14

Remove from the oven and let rest for 5 minutes before serving.

Nutrition Facts

Serving size	(1452.0g)

Amount per serving	% Daily Value*
Calories	2196.6

Total Fat 178.0g	0%
Saturated Fat 88.2g	0%
Polyunsaturated Fat 3.4g
Cholesterol 342mg	0%
Sodium 4251.4mg	0%
Total Carbohydrate 106.7g	0%
Dietary Fiber 24.1g	0%
Total Sugars 27.8g
Protein 36.8g	0%

Vitamin D 15.9IU	0%
Calcium 697.9mg	0%
Iron 7.9mg	0%
Potassium 2439.5mg	0%

*The % Daily Value tells you how much a nutrient in a serving of food contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.

Source of Calories

Fat: 73.6%

Protein: 6.8%

Carbs: 19.6%