In a large bowl, whisk together the flour, oats, brown sugar, baking powder, baking soda, salt, and cinnamon.
In a medium bowl, combine buttermilk, melted butter, eggs, and vanilla extract. Whisk until combined.
Pour wet ingredients over dry ingredients and stir until combined. Let pancake mixture sit for at least 20 minutes. You can cover and put the mixture in the refrigerator for 3-4 hours before making the pancakes.
When ready to cook, heat a griddle or pan to medium low heat. Coat with cooking spray. Drop about a 1/4 cup of batter onto heated skillet. Cook until surface of pancakes have some bubbles and a few have burst, 1 to 2 minutes. Flip carefully with a spatula, and cook until browned on the underside, 1 to 2 minutes more. Continue making pancakes until the batter is gone.
Serve pancakes with fruit and maple syrup, if desired.
Note-these pancakes freeze well. Let them cool completely and then wrap in plastic wrap and put in a freezer bag. When ready to eat, remove from freezer and reheat in microwave or the toaster.