Preheat the oven to 350 degrees.

In a medium bowl, combine the flour, cocoa, baking soda, baking powder, and salt; set aside.

In a large bowl, or the bowl of a standing mixer, cream together the butter and sugar until light and fluffy. Add the eggs, one at a time, beating until just combined. Stir in the vanilla.

Sprinkle 1/3 of the flour mixture into the mixing bowl and mix until just combined. Add half of the sour cream, mixing until just combined. Repeat, alternating the remaining flour in 2 more additions with the remaining sour cream in one more addition (ending on flour).

Pour one third of the batter into a 9x13 inch metal or glass pan that has been greased lightly and floured. Place rows of peppermint patties into the pan so none are touching. Pour the remaining batter on top. Bake for 20 minutes or until toothpick comes out clean.

Transfer to a wire cooling rack and allow to cool completely before frosting.