Preheat oven to 350°F. Line muffin tin with cupcake liners.
Combine the cake mix, pudding mix, sour cream, water, oil, and eggs in a large mixing bowl.
Beat with electric mixer for two minutes.
Fill each baking liner 1/4 full. Set a frozen Cadbury Egg in wide side down into the center of the liner.
Top each Cadbury Egg with a tablespoon of batter (it will fall around sides).
Bake for 12-15 minutes or until a toothpick inserted into the sides comes out clean. (Cadbury Egg will be in center).
Allow to cool.
For frosting, cream butter and cocoa powder. Add vanilla extract. Alternate heavy cream with powdered sugar until frosting consistency reached. For thicker frosting, add more powdered sugar. For a looser frosting, add more cream (or milk).
Pipe each cupcake with frosting and drizzle with caramel sauce for a garnish.