Preheat your oven to 350°F and bring 10 cups of water to a boil in a large pot.
Trim the ends off your fresh green beans and cut them in half. Boil them until tender—about 10-15 minutes.
1 pound fresh green beans
Dice your onions and mince your garlic.
1 large yellow onion, 3 cloves garlic
Once your green beans are tender, strain them and dry them off with a kitchen towel. Add cooked green beans, onions, garlic, and porcini mushrooms to a frying pan with salt, pepper, and olive oil over medium heat until onions are transparent.
¼ cup dried porcini mushrooms, ½ teaspoon black pepper, 1 pinch of salt, 2 tablespoons olive oil
Add cream of mushroom soup and mix well. Simmer on low for about 5 minutes to reduce excess moisture.
21 ounces cream of mushroom soup
Transfer your green bean mixture to a 10.5" x 7.5" oven-safe casserole dish. Top with a thin layer of cheese, and finalize with a layer of crispy fried onions.
4 ounces cheddar cheese, 2.8 ounces crispy fried onions
Bake for 30-35 minutes until cheese is nice and melted and crispy onions are starting to brown.