Prepare cake batter and pour in an 8x3 cake pan and an 8 inch dome pan. You may need to double the recipe that's linked in the recipe card.
Bake cakes and allow them to cool completely.
While the cakes and baking the cooling, prepare the chocolate buttercream icing and black frosting.
Use a sharp serrated knife to trim the sides of the cake (if necessary) to ensure the overall width or diameter of both cakes is the same.
Place the round cake on a cake stand.
Push 5 dowels around the middle of the cake for support.
Spread icing on top of the cake.
Place a cake board (same width as the cake) on top and press gently to secure into place.
Spread icing on top of the board.
Place the dome cake on top of the icing and press gently to secure into place.
Use a spatula to frost the entire cake smoothly in icing.
Chill cake in the refrigerator for 20 minutes.
Fill a piping bag with chocolate icing and attach Wilton star tip # 18 or 21.
You will start piping from the bottom of the cake and work your way upwards. Hold the piping bag at a 45 degree angle along the base of the cake. Squeeze bag until icing comes out and sticks to the cake and gently pull away to pipe a pointy star. Continue doing this until the entire cake is covered is buttercream stars.
To make ears, push two chocolate chip cookies on top on the cake. Pipe buttercream stars along the edges of the cookies.
Fill a piping bag with black icing and a small round tip. Pipe a nose and mouth on top of a cookie.
Stick this cookie on the frontal area of the cake.
Finally, stick the two large sprinkle eyes above the nose and enjoy.