Preheat your oven to 325°F.
In a mixing bowl, combine the cake mix, pudding mix, sour cream, eggs, heavy cream, espresso powder (if using), milk, and vegetable oil. Mix until smooth, either by whisking or using a stand mixer with the paddle attachment.
Gently fold in the peanut butter chips using a rubber spatula.
Grease a mini bundt pan with butter and dust with flour to prevent sticking. Tap out any excess flour.
Fill each tin with batter, filling them about 2/3 of the way to the top.
Bake in the preheated oven for 20 to 25 minutes, or until a toothpick inserted into the center comes out clean.
While the cakes bake, prepare the frosting. Beat together the cream cheese, butter, powdered sugar, vanilla, and cream until smooth and creamy.
Once the cakes are done baking, let them cool for 15 minutes before removing them from the pan and allowing them to cool completely.
When the cakes are completely cooled, pipe peanut butter onto each cake, starting from the outside and working your way to the center.
Repeat the piping process with the cream cheese frosting.
Enjoy! Store any leftovers in the fridge for a chilled treat later on.