In a mixing bowl, mix the flour, quick oats, brown sugar, baking powder, salt, and cinnamon. Pour the melted butter over the dry ingredients. Use a fork to mix until combined.
1 1/2 cups All-purpose flour, 1 1/4 cups Quick oats, 3/4 cup Brown sugar, 1/2 tsp Baking powder, 1/2 tsp Salt, 1/2 tsp Ground cinnamon, 3/4 cup Unsalted butter