Because of the filling, it is normal for the tops of the cupcakes to sink as they cool.
I find the frosting works best if I mix it up then refrigerate it for 30-45 minutes before using it. You can beat it again with your hand mixer to make it fluffy.
Store remaining cupcakes and frosting in refrigerator.
Nutrition Facts per Cupcake (Including Frosting):
Fat: 24 grams
Net Carbs: 3
Protein: 8 grams