This Minnie Mouse cake is so easy to create! I just used full size muffin tins to bake my chocolate cupcakes and used the star tip to cover in deep chocolate icing. Actually looks better than changing to black!
For the face I used a 13" round pan and after crumb-coating, I used a toothpick to draw Minnie's features (excluding the bow) into the icing. Once complete, outline all the features in chocolate icing. Fill in the large areas with a star tip. Deep chocolate icing where the black parts would be and white icing (reserve about a cup for the eyes/tongue/bow) tinted with a bit of cocoa powder or some of your chocolate icing mixed in (little amounts at a time - don't overdo it) for her "skin" colour.
Fill in her eyes with white and her tongue with pink. For her bow I drew her bow on a piece of parchment paper, make sure the size is relative to her face. Using store-bought cookie dough (like a Pillsbury tube) or your favourite sugar cookie recipe, fill the bow in with dough and bake according to the directions. You might want to slightly overbake to give the cookie a bit more firmness. If the cookie spreads during baking - while still hot, cut out the shape with a sharp knife and push the excess away from the bow.
Let cool completely. Transfer to a cooling rack. Once cooled, tint your remaining icing pink and microwave it on high for 7 seconds, stir. Repeat this process until your icing is pourable and will coat a spoon. Place your cooling rack over a baking sheet and pour your icing over the cookie until it is completely covered. Let dry completely. Scrape the dripped icing off the pan and microwave it again for a few seconds at a time, stirring in between until it can coat a spoon. Tint your icing a deeper pink and pour it carefully in tiny dots to make your polka dots. Let dry.
Once your cookie is dry, place it on Minnie's head, arrange your cupcakes as ears and voila!