14 Ratings. Bright and fresh lime flavor that’s a little tart, a little sweet, that makes for a bright summery dessert. Transfer the frosting to a piping bag with a decorative tip and pipe the frosting onto the cupcakes. Key Lime Cupcakes have all the flavors of key lime pie in a pretty little cupcake. Serve immediately or chill for up to 3 days . Reviews. If desired, top each cupcake with half of a key lime slice. A citrus dessert is the best kind of dessert when it’s hot outside. Add the key lime zest and 3 tablespoons of the key lime juice, mixing well and adding additional key lime juice as needed to reach a good piping consistency. Sprinkle cupcakes with additional key lime zest and Graham Crumble. Add Rating & Review. Advertisement.