Preheat oven to 350°.Combine cake mix, pudding, sour cream, oil, water, and eggs in electric mixer with paddle attachment. Beat together on medium for 5 minutes until fluffy and thoroughly combined.

Scoop cake batter into mini cake pans and bake for 20 minutes (if small cake pans). Adjust your timing if using the sheet roll method or larger cake pans. Cake is done when a toothpick inserted in the center comes out clean.

Cream butter with electric mixer until light and fluffy.

Add in powdered sugar, alternating with cream (or milk) until thick and fluffy.

Add in peppermint extract and whip for 2 minutes on medium.

Fill piping bag with peppermint buttercream. Set aside

Use a serrated knife to gently cut each mini cake into 2 or 3 layers. Fill with piped frosting.

Garnish with peppermint candies!