If you love the combination of chocolate and peanut butter, you will adore these Reese's chocolate peanut butter cup cupcakes! They feature both Reese's Peanut Butter Cups and Reese's Pieces peanut butter candies along with a soft and fluffy chocolate cupcake, and super creamy peanut butter buttercream frosting.
Adjust the oven rack to the center of the oven and preheat the oven to 350°F.
Line 12 standard muffin cups with paper liners. Grease the insides of the liners and set aside.
To make the cupcakes: Sift together the flour, cocoa powder, baking soda, salt, and baking powder in a bowl.
In the bowl of an electric stand mixer fitted with the paddle attachment, beat together the butter and sugar about 5 minutes until smooth. Add the egg and mix until smooth. Scrape down the sides of the bowl.
Stir in half of the dry ingredients on low speed. Then mix in the milk until combined. Finally stir in the other half of the dry ingredients and mix just until smooth but don't overmix.
Add about 1 ½ to 2 tablespoons of batter to each cup and top with a peanut butter cup (do not press it down). Cover with the remaining batter and carefully smooth it out to cover the entire cup to the edges of the liner. Bake the cupcakes for about 20 to 22 minutes, or until a toothpick inserted into the center comes out clean. Cool cupcakes completely.
To make the buttercream: In the bowl of an electric stand mixer fitted with the paddle attachment, beat together the butter, peanut butter, and salt until smooth and creamy, about a minute.
Scrape down the sides of the bowl and add the confectioners’ sugar. Beat together until on low speed until just combined, then scrape down the sides of the bowl and beat again on medium-high speed for a few more minutes until light and fluffy.
Fill a pastry bag fitted with whatever large piping tip you prefer (I recommend a large closed star tip) and frost the cupcakes. Decorate each cupcake with a few Reese’s Pieces candies, if desired. I like using one of each color per cupcake.
This batter rises quite a bit. It may not look like a lot especially when you split it beneath and on top of the peanut butter cups but it will rise all the way to the rim of the pan when baked.
You definitely want to sift the confectioners' sugar so you don't have lumps in your frosting. Especially when using a closed star tip to decorate, lumps can get stuck in there and make a big mess when trying to pipe evenly.
If the peanut butter cup sinks or gets pushed to the bottom of the cupcakes it can get stuck to the liner and be very difficult to peel off. Here are some tips to avoid that happening:
Lightly grease the cupcake liners with pan spray.
Be generous in how much batter you put in the bottom, using a minimum of 1 ½ tablespoons but up to 2 tablespoons is fine too.
Do NOT press the peanut butter cups down into the batter.
When you cover with the remaining batter, gently smooth it out without pressing down more.
Do not rap the pan down on your counter to even out the batter. It can cause the cups to sink down.
Even if your peanut butter cups sink and stick (hey it happens to the best of us sometimes) it's just the bottom layer of chocolate, and the rest of the cupcakes are still delicious!