Preheat your oven to 350°F (175°C)
Grease a muffin pan or use a silicone muffin pan or muffin baking cups
Open and drain the green beans and put them in a large bowl
Add the cream of mushroom soup, the shredded cheese, the French-fried onions and the salt and pepper. Stir to combine and set aside
Cut the puff pastry sheet into 12 equal squares and place a square in each muffin cup.
Using an ice cream scoop or a large spoon, fill the muffin cups with the green bean mixture almost to the top.
Add a little extra shredded cheese and crispy fried onions to the top of each cup.
Bake the mini green bean casseroles for approximately 25 minutes or until bubbly and the tops are turning golden brown.