In a mixing bowl, whisk together the rolled oats, whole wheat flour, brown sugar, baking powder, baking soda, salt, and cinnamon.
In another bowl, whisk together the milk, Greek yogurt, egg, vanilla extract, and melted butter.
Gradually mix the wet ingredients into the dry ingredients until just combined. Let the batter rest for 5 minutes to soften the oats.
Preheat a griddle or non-stick skillet over medium heat and lightly grease with butter or oil.
Scoop 1/4 cup portions of batter onto the griddle, spreading slightly if needed.
Cook until bubbles form on the surface and the edges start to set, about 2 minutes. Flip and cook for another 1-2 minutes, or until golden brown.
Repeat with the remaining batter.
Serve warm with maple syrup, fresh fruit, or a dollop of yogurt.