Preheat oven to 350°F (175°C). Line a muffin tin with paper liners.
In a large bowl, mix the cooked quinoa, oat flour, baking powder, baking soda, salt, and cinnamon.
In another bowl, whisk together the eggs, maple syrup, applesauce, and vanilla extract.
Pour the wet ingredients into the dry ingredients and mix until just combined. Fold in the diced apple.
Spoon the batter into the prepared muffin tin, filling each cup about ¾ full.
Bake for 20-25 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Let the muffins cool in the tin for 5 minutes, then transfer to a wire rack to cool completely.