Monogram Heart Cupcakes

Make fondant hearts: Using a small rolling pin, roll out half the fondant to about 1/8 inch on a work surface lightly dusted with cornstarch.
Blot one of the monogram stamps in cornstarch, and quickly but gently press stamp into the fondant.
Repeat, blotting stamp each time in cornstarch and leaving about 3 inches between each imprint, until entire surface has been stamped.
Cut out hearts by centering and pressing a 2-inch heart-shaped cookie cutter over each imprint.
Remove all excess fondant from around the cutout shapes; roll out again, and stamp and cut out more hearts.
Repeat with remaining fondant, using the other monogram stamp if making cupcakes for a couple, to make an equal number of hearts with the two stamps.
Using an offset spatula, carefully transfer fondant hearts to parchment-lined baking sheets; let stand at room temperature until completely dry and firm, about 1 day.
Hearts can be stored in an airtight container, between layers of parchment or waxed paper, until ready to use (they will keep for several months).
Tint buttercream desired shade with gel-paste food color.
Transfer to a pastry bag fitted with a large French star tip (Ateco #867).
Pipe frosting onto each cupcake, swirling the tip and releasing pressure as you pull up to form a peak.
Cupcakes can be refrigerated, uncovered, up to 1 day.
To finish, bring cupcakes to room temperature and insert fondant hearts upright into frosting.