Brush each side of the wonton wrappers with melted butter and place into muffin tin. Bake 7-8 minutes or until browned and crisp.
Mix drained green beans, mushroom soup, 1 cup cheddar, ¼ cup crispy onions, and black pepper in a bowl. Fill the wonton cups with the mixture.
Gently crush the remaining onions and combine with remaining cheese. Sprinkle over the bean mixture.
Bake for 10-12 minutes or until cheese is melted and wontons are browned.
Cool for about 3 minutes and serve warm.
Notes
French fried onions are sometimes called French's Fried Onions, since that is the most common brand name.
Cook wonton wrappers and prepare the filling ahead of time and refrigerate separately until ready to bake.
Refrigerate cooked and filled wonton cups for 2-3 days, or freeze for up to a month. Freeze on a parchment-lined cookie sheet, then transfer to an airtight container.
Reheat in a 350°F oven for about 10 minutes or until heated through.