If you have only one pan and a recipe calls for more cupcakes than your pan will make, cover and refrigerate the rest of the batter while baking the first batch. Cool the pan about 15 minutes, then bake the rest of the batter, adding 1 to 2 minutes to the bake time.
Only have regular size muffin cups? Just use slightly less than 1/4 cup batter and slightly less than 1 tablespoon filling. Bake 19 to 21 minutes.