• Preheat the oven to 350 degrees and place muffin cupcake liners into tins.
• In a medium bowl, add flour, baking powder, baking soda and salt and whisk for about 45 seconds.
• Using a mixer, in a large bowl add the peanut butter, oil, and brown sugar and beat until combined.
• Add eggs and maple syrup or vanilla extract and continue beating until just combined.
• Alternately add the flour and buttermilk to the wet mixture, beating just until combined and do not overbeat. (A few small lumps of flour is fine, overbeating will result in a dry, dense cake.
• Using an ice cream scoop, scoop batter into the muffin tins.
• Place 1 Reese cup in each cupcake by slightly pushing in, don't over-push or it will go to the bottom of the cupcake
• Bake for about 15 minutes or test by using a toothpick and poking the center of cupcake. It should still be moist, if it's dry, it will be overbaked and dry.
• Transfer cupcakes to baking rack and place another Reese cup on top of the one already inserted. Let cool.

Peanut Butter Mousse Frosting

• Cream butter and add in all other ingredients until combined and creamy.
• Place frosting into a piping bag, or snip a 1/3 inch inch hole into a ziplock bag using scissors for the bag.

Chocolate Ganache Glaze

• Microwave the heavy cream in the microwave for 2-3 minutes or starting to boil.
• Add in chocolate and peanut butter chips and let sit for a minute or two then whisk for a couple of minutes.
• Dip the cooled peanut butter cupcake tops into the ganache one by one and let them cool.
• Pipe frosting in circular motions starting outward working in to the middle.
• Cut up some random Reese cups and sprinkle on top.