Here are a few thoughts which may be helpful for those of you who are struggling with this problem:-
Many will jump to the conclusion that it is the fault of the paper cases. This is far from correct in the majority of cases. Admittedly there are inferior baking cases, so we would recommend that you always buy good quality cases which are usually thicker.
Make sure your recipe is a good, reliable one, as a mixture that contains too much fat / liquid, means a moist, greasy exterior of the sponge causing a peeling of the paper cases. Always check that you have weighed ingredients accurately! Too much moisture will cause peeling!
Bake as close to the date required as possible, therefore there is less storage time. Bake in cases inside a deep muffin tin, and fill to ¾ full so that the mixture rises just to the top of the case, and will ‘grip’ the top with no overflowing.
Ovens vary – if you do a lot of baking you will know your oven, and so should not have the problem of an oven too hot / too cool. If in doubt, invest in an oven thermometer to check it. Most people would agree that underbaked cakes can be too moist on the outside causing the cases to peel, as will overbaked, which means a certain amount of shrinkage from the cases. So do ensure that your cakes are baked for just the correct amount of time. If in doubt always add a couple of minutes.
After removal from the oven, transfer to a cooling rack where the air can circulate around the whole cake, including the base. This allows the steam to escape and the cake to dry out.
If you add the icing, whether buttercream or sugarpaste, as soon as possible after cooling completely,it will seal the sponge and keep it fresh within the case.
Place the decorated cupcakes inside a cardboard cupcake box which keeps them fresh but not quite airtight. This also means that the cakes in their cases are supported inside each cavity of the box, and the moisture does not build up.
Never store in an airtight tin / plastic container. This can cause more moisture and condensation to form, causing immediate peeling of the cases.
There can be a risk of peeling cases if you freeze the cupcakes, but if you need to make the cupcakes in advance, always freeze them, completely airtight, as fast as possible, then de-frost with air circulating around them at room temperature, and decorate as soon as completely thawed out. It is a good idea to open freeze them first on a tray - this will ensure they keep a good shape, then place into a box for protection.
Always ensure you buy good quality cupcake products!