# What you'll need:
→ Vegetables
01 - 2 lb fresh green beans, trimmed and cut into 2-inch pieces (or frozen cut green beans, thawed and drained)
→ Sauce Base
02 - 2 tbsp unsalted butter
03 - 9 oz cremini or button mushrooms, sliced
04 - 1 small yellow onion, finely chopped
05 - 2 garlic cloves, minced
06 - 2 tbsp all-purpose flour
07 - 1 cup whole milk
08 - ½ cup heavy cream
09 - ½ cup low-sodium vegetable broth
10 - 1 tsp salt
11 - ½ tsp black pepper
12 - ½ tsp ground nutmeg (optional)
→ Topping
13 - 1½ cups crispy fried onions (store-bought or homemade)
# Method:
01 - Set the oven to 350°F (180°C) to heat while preparing the ingredients.
02 - Bring a large pot of salted water to a boil. Add green beans and cook for 5 minutes until just tender and bright green. Drain and immediately rinse under cold water to halt cooking. Set aside.
03 - In a large skillet over medium heat, melt butter. Add mushrooms and cook 5–6 minutes until browned and tender. Stir in onion and garlic; cook an additional 2–3 minutes until softened.
04 - Sprinkle flour over the sautéed vegetables and cook, stirring constantly, for 1 minute. Slowly whisk in milk, cream, and vegetable broth. Bring mixture to a simmer and cook until thickened, about 5 minutes. Season with salt, black pepper, and nutmeg if using.
05 - Add the drained green beans to the skillet and toss gently to coat evenly with the sauce.
06 - Transfer the green bean mixture into a 2-quart baking dish. Evenly sprinkle half of the crispy fried onions over the top.
07 - Bake in the preheated oven for 25 minutes until the casserole is bubbling.
08 - Remove from oven, sprinkle remaining fried onions on top, and bake for an additional 5–7 minutes until the onions are golden and crisp.
09 - Allow the dish to rest for 5 minutes before serving to let flavors meld.
