Piped-Buttercream Rose Cupcakes

Cut parchment paper into squares to fit on top of flower nail (#7).
Tint buttercream red with gel-paste food color.
Dab buttercream on top of nail to secure parchment.
Fit a pastry bag with only a coupler; fill with buttercream.
Squeeze pastry bag gently; pull up slowly to make an acorn-shape mound on top of the square.
Secure a small petal tip (#103) to the coupler.
(If you need both hands to attach the tip, anchor the nail in a block of polysterene or in a potato with a flat-cut bottom.)
Holding tip against the point of the buttercream mound, wide end down and the narrow end angled in toward the acorns center, pipe a wide strip as you turn the nail, enveloping the top completely.
Turning the nail as you go, make two slightly arched petals that each reach around half of the circumference of the acorn.
Continue turning the nail, making longer petals that overlap, and angling farther outward as you go, until you have piped a full rose.
Gently slide the parchment with the rose off the nail and onto a baking sheet, and refrigerate at least 20 minutes (or up to 2 days).
Repeat to make 24 roses.
Using a serrated knife, trim tops of cupcakes to make level.
Using an offset spatula, spread buttercream over cupcakes.
Use a clean offset spatula to gently transfer buttercream roses onto frosted cupcakes (discard parchment).
Cupcakes can be refrigerated up to 3 days in airtight containers; bring to room temperature before serving.