Ice cream cupcakes -- what a way to combine two birthday favorites into one sweet treat! To make them, whip up cake batter (or yummy brownie mix) and fill muffin cups only about halfway or less (about 1 tablespoon of batter, give or take depending on the size of your pan). Bake and cool.
Fill the remaining space in the cup with ice cream and put the whole pan into the freezer. Decorate them just before you're ready to serve.
Also consider an alternative method: bake cupcakes as you normally would and allow them to cool completely. Instead of decorating with a traditional frosting and other goodies, frost them with a scoop of your birthday boy or girl's favorite ice cream flavor.
Either way, serve immediately so the ice cream doesn't melt!