Fresh Green Bean Bake

Preheat your oven to the optimal temperature of 350 degrees Fahrenheit (175 degrees Celsius). To chill the ingredients, fill a large container with ice and cold water.

Fill a large cooking vessel with salted water and bring it to a boil. Add green beans and cook them uncovered until they reach the desired level of crispiness, approximately 6 minutes. Drain the green beans in a colander and then immediately submerge them in ice water to halt the cooking process. Drain the green beans again and transfer them to a large serving container.

Place 3 tablespoons of butter in a large skillet over medium-high heat. Add sliced onions and sauté them until they become translucent, around 5 minutes. Then, add sliced mushrooms and minced garlic; sauté them until the mushrooms are cooked through, roughly 5 minutes. Stir in the green beans.

Place 5 tablespoons of butter in a microwave-safe bowl. Heat it on high power for short intervals, until the butter is fully melted.

Whisk flour into the melted butter until a smooth mixture forms. Season it with sea salt and black pepper to taste. Add 1 cup of milk; whisk until the mixture is smooth and well combined. Microwave it for 2 minutes, then add another cup of milk; microwave again for 2 minutes. The mixture should thicken as you add more milk, becoming less thick with each addition.

Transfer the green bean mixture to a 9x13-inch baking pan. Stir in the thickened roux mixture until it's fully incorporated. Season with salt and black pepper to taste.

Place the green bean mixture in the preheated oven and bake until it's warm and bubbly, approximately 30 minutes. Top the dish with crispy fried onions and return it to the oven for an additional 5 minutes.