The maple caramel filling:
The real magic here is in the filling: a quick maple caramel that takes only minutes to whip up. This caramel is simple, but make sure not to overcook it; look for a gentle boil and a slight thickening before adding the cream. If you want to go nut-free, swap the peanut butter for almond or sunflower seed butter.

Storage & make ahead:
Both the caramel and buttercream can be made up to 1 week ahead and stored in airtight containers in the fridge. For the fluffiest texture, bring the buttercream up to room temperature and re-whip it before using. Once assembled, the cupcakes can be kept covered at room temperature for up to 2 days or refrigerated for up to 5 days (bring to room temperature before serving). They also freeze great. Just leave off the buttercream and caramel until ready to serve, then thaw and finish decorating.