Preheat your oven to 375 degrees F and line a couple of baking sheets with parchment paper or a silicone baking mat set aside.
In a medium bowl, whisk together the flour, baking powder, baking soda, ground cinnamon, nutmeg, and salt. Set aside.
In a much larger bowl, mix together the butter, brown sugar, and granulated sugar with a handheld electric mixer or in the bowl of your stand mixer until smooth. Add the eggs and then mix. Add the vanilla extract and then mix again.
Add the flour mixture to the butter mixture and mix again until smooth. Stir in the oats, chocolate chips, white chocolate chips, shredded coconut, walnuts and corn flakes until thoroughly combined. At this point, you may chill the cookie dough if you like. It will help to keep them from spreading too much in the oven. I chilled mine for about 30 minutes.
Scoop the dough (I used a standard cookie scoop) onto the prepared baking sheets, and bake in batches as needed. Bake for 12-15 minutes or until slightly brown around the edges. Remove from oven and let cool for about 3 minutes on the baking sheet before transferring them to a wire rack.
Enjoy immediately or place them in an airtight container to enjoy later!