# Components:
→ Vegetables
01 - 2 lb fresh green beans, trimmed and cut into 2-inch pieces or 2 lb 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
# Directions:
01 - Set the oven to 350°F (180°C).
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 - Melt butter in a large skillet over medium heat. Add mushrooms and cook for 5-6 minutes until browned and tender. Incorporate onion and garlic, cooking for an additional 2-3 minutes until softened.
04 - Stir in flour and cook for 1 minute while stirring constantly. Gradually whisk in milk, cream, and vegetable broth. Simmer and cook until the sauce thickens, 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 mixture into a 2-quart baking dish. Evenly sprinkle half of the crispy fried onions over the top.
07 - Bake for 25 minutes until the casserole is bubbling. Remove from oven, add the remaining fried onions, and continue baking for another 5-7 minutes until golden and crisp.
08 - Allow to cool for 5 minutes before serving.
