Preheat your oven to 350 degrees F.

Combine butter and brown sugar with mixer until well combined. Add in eggs, one at a time, followed by your vanilla.

Add one cup of flour and your baking powder (and salt if using) to batter and mix well to combine. Add in the remaining flour, one cup at a time, mixing until well combined.

Add in 1/4 cup of your M&M's, your candy corn and any other optional mix ins.

Press about 1/3 of your dough into the bottom of an 9x11" pan that has been sprayed with cooking oil. I lined my pan with foil, and then sprayed.

After covering bottom of your pan with batter, add a layer of your Candy Corn Oreo Cookies.

Press the remaining batter onto the cookie layer, covering entirely.

Top with remaining 1/4 cup Candy Corn M&M's.

Bake for 30-40 minutes until lightly browned on top. You will want them to still be moist, but not gooey.

Enjoy!