Bake and cool cake. Prepare batter following recipe directions. Place bakeware on cookie sheet. Bake and cool cakes following package directions.
Decorate cakes. Prepare buttercream icing following recipe directions. Use rose icing color to tint icing pink. Reserve small amount of white icing. Use 9 in. angled spatula and pink icing to ice top of cake smooth.
Use 9 in. fondant roller with purple guide rings to roll out red fondant 1/16 in. thick. Use medium cut-out from set to cut heart. Place red heart on the center of cake. Roll out white fondant 1/16 in. thick. Use small cut-out from set to cut heart. Brush white heart with damp brush to secure to the center of red heart.
Use tip 3 and reserved white icing in cut disposable bag to pipe dots.