Preheat the oven to 325°F (165°C) and line a baking sheet with parchment paper.

In a large bowl, mix oats, whole wheat flour, baking powder, cinnamon, and salt.

In a separate bowl, whisk together melted coconut oil, egg, vanilla extract, and maple syrup until smooth.

Add the wet ingredients to the dry ingredients, stirring until just combined, then fold in the diced apple.

Scoop tablespoon-sized portions of dough onto the baking sheet, flattening slightly with a spoon.

Bake for 12-15 minutes or until the edges are lightly golden. Cool on the sheet for 5 minutes before transferring to a wire rack.