# Components:
→ Vegetables
01 - 2 lb fresh green beans, trimmed and cut into 2-inch pieces (or frozen, thawed and drained)
→ Sauce Base
02 - 2 tablespoons unsalted butter
03 - 9 oz cremini or button mushrooms, sliced
04 - 1 small yellow onion, finely chopped
05 - 2 garlic cloves, minced
06 - 2 tablespoons all-purpose flour
07 - 1 cup whole milk
08 - ½ cup heavy cream
09 - ½ cup low-sodium vegetable broth
10 - 1 teaspoon salt
11 - ½ teaspoon black pepper
12 - ½ teaspoon ground nutmeg (optional)
→ Topping
13 - 1½ cups crispy fried onions (store-bought or homemade)
# Directions:
01 - Set the oven temperature to 350°F.
02 - Bring a large pot of salted water to a boil. Add green beans and cook for 5 minutes until just tender but still bright green. Drain and rinse under cold water to halt cooking; set aside.
03 - In a large skillet over medium heat, melt butter. Add mushrooms and cook for 5-6 minutes until tender and browned. Add onion and garlic; cook an additional 2-3 minutes until softened.
04 - Stir in flour and cook for 1 minute stirring constantly. Gradually whisk in milk, cream, and vegetable broth. Simmer until thickened, approximately 5 minutes. Season with salt, pepper, and nutmeg if using.
05 - Add the drained green beans to the skillet and toss to coat evenly with the sauce.
06 - Transfer the mixture to a 2-quart baking dish. Sprinkle half of the crispy fried onions evenly over the top.
07 - Bake for 25 minutes until the casserole is bubbling.
08 - Remove from oven, sprinkle remaining fried onions on top, and bake for an additional 5 to 7 minutes until golden and crisp.
09 - Allow the dish to cool for 5 minutes before serving.
