In a large bowl, whisk together the flour, sugar, baking powder, baking soda, and salt.
In a separate bowl, whisk the buttermilk, egg, and melted butter until combined.
Pour the wet ingredients into the dry ingredients and stir until just combined; do not overmix.
Heat a non-stick skillet or griddle over medium heat and lightly grease with cooking spray.
Using a 3-inch round mold or measuring cup, pour batter to form small pancakes. Cook until bubbles form on the surface, about 2-3 minutes, then flip and cook an additional 1-2 minutes until golden brown. Repeat until all batter is used, making 12 pancakes total. Set aside to cool.
In the same skillet, cook the breakfast sausage patties over medium heat until browned and cooked through, about 3-4 minutes per side. Drain on paper towels.
To assemble each McGriddle, place one pancake on a clean surface, top with one sausage patty, then a slice of American cheese, and finally another pancake to form a sandwich.
Wrap each sandwich tightly in plastic wrap and then in aluminum foil for freezer storage.
To reheat, remove foil and plastic wrap, wrap sandwich in a paper towel, and microwave on high for 1-2 minutes or until heated through. Alternatively, reheat in a 350°F oven wrapped in foil for 15-20 minutes.