Preheat Oven:
Preheat your oven to 325°F (165°C) and line a baking sheet with parchment paper or a silicone baking mat.
Mix Dry Ingredients:
In a large bowl, combine oats, flour, baking powder, cinnamon, nutmeg, and salt. Stir to mix well.
Prepare Wet Ingredients:
In a medium bowl, whisk together melted coconut oil, honey or maple syrup, egg, and vanilla extract.
Combine Ingredients:
Pour the wet ingredients into the dry ingredients and stir until just combined. Fold in the diced apple pieces.
Shape the Cookies:
Scoop 1 1/2 tablespoons of dough and roll into a ball. Flatten slightly and place on the prepared baking sheet, leaving space between each cookie.
Bake:
Bake in the preheated oven for 12–15 minutes, or until the cookies are set and lightly golden around the edges.
Cool:
Remove the cookies from the oven and let them cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.