Preheat the oven to 350°F. Line two baking sheets with parchment paper.

In a small bowl, whisk together flour, baking powder, cinnamon, nutmeg and salt. Set aside.

In a large bowl, combine banana, maple syrup, oil, egg, and vanilla. Whisk until smooth.

Stir the flour mixture into the wet ingredients until barely combined. Fold in the oats, raisins, and flaxseeds until evenly distributed. The mixture will seem a little wet.

Using a medium spring-loaded cookie scoop, level, and roll about 1.5 tablespoons of the cookie dough and place it on one of the prepared baking sheets, spaced at least two inches apart.

Bake for 10-12 minutes, or until lightly brown on the edges and firm on the top.

Remove from the oven and let the cookies cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.