Preheat oven to 400. Set aside puff pastry to thaw until it’s soft enough to handle.
Make your casserole filling by adding olive oil to a medium skillet. Add shallot and garlic and cook for 2-3 min. Add in sliced mushrooms and season with salt and pepper. Cook for about 4-5 min or until mushrooms release their liquid and soften.
Add in cream of mushroom soup, heavy cream and soy sauce. Season to taste with salt and pepper.
Wash green beans and add about 5 in a row to a parchment lined baking sheet. Add a dollop of mushroom mixture and a sprinkle of grated cheese. Make sure the cheese gets in between the green beans as this will help everything stick together.
Roll puff pastry out on a floured surface. Slice rectangular squares to fit over your green bean mix. Pinch edges to close and brush with egg wash. Repeat with the remaining squares. Bake for 15 min.
Switch oven to broil and carefully, flip each pastry. Add a little more cheese, and a sprinkle of fried onions. Broil for about 3 min or until golden brown. Enjoy!
