Melted Cheese BBQ Brisket Sandwiches

Ingredients:

1 pound cooked brisket, shredded

1/2 cup BBQ sauce (your favorite)

4 slices sourdough bread

1 cup shredded cheddar cheese

1 tablespoon unsalted butter

1/2 cup caramelized onions (store-bought or homemade)

Salt and freshly ground black pepper, to taste