Preheat your oven to 180° C (350° F), line a baking sheet with parchment paper or lightly grease with butter.
In a medium mixing bowl, add the flour, baking powder, salt, cinnamon, and nutmeg. Whisk together then set aside.
In a large mixing bowl, add the butter and sugar and cream together. Mix in the eggs one at a time then mix in the vanilla.
Add half the flour mixture to the wet mixture, mix together until well combined, then add the remaining flour mixture and mix again until well combined.
Add the oats and trail mix, and mix together until they are evenly distributed throughout the cookie dough.
Drop by heaping tablespoon onto the prepared baking sheet.
Bake for 12-15 minutes or until the cookies are lightly browned around the edges. Remove from oven and allow to cool on the sheet for 3-5 minutes.
Remove to a wire rack to cool completely.
Serve and enjoy.