Here are two relatively simple Valentine cupcakes you can make, both using marshmallow fondant. Preparation for both kinds of cupcakes is the same.
1. Level the hump of the cupcake with a cake knife.
2. Pipe an even layer of buttercream on top of the cupcake but do not go all the way over to the edge. This will prevent it from coming out from the edges of the fondant that lays on top.
3. Roll the fondant out to 1/8" thick and use a 2-1/2" circle
cutter to cut out as many circles as you have cupcakes.

The Teddy bear valentine cupcakes are made by pressing a rubber stamp into the fondant.
Roll out white fondant to 1/8" thick. Use the
circle cutter to
cut out the same number of circles as you have in cupcakes.
Press the
rubber stamp down in the center of each cirle. Now lift away the excess
fondant and wrap it up.
Place each circle of fondant on top of a cupcake.
The colors used for the teddy bears are copper, black, blue, pink,
green. Use a fine paint brush to paint each color in the appropriate
area of the stamped picture.
Keep a paper towel handy to dab the
paintbrush on. Only slightly wet the paintbrush before dipping it in a
tiny dab of food color paste. Make sure the brush is not too wet. If
the brush is too wet, the colors will run.
Finish the edge of the valentine cupcakes off with a snail trail border using tip
#4.
Follow steps 1 - 3 above using pink fondant.In
the spaces between the circles, cut out some of the smaller hearts.
Use the fondant trimmer
with the zig zag wheel to impress the design into the fondant. Go
straight across the middle vertically, then two more evenly spaced
lines on each side. Now do the same thing horizontally.
Place all the
fondant circles on the valentines day cupcakes. Gather up excess
fondant, smush it back into a ball and roll it out again.
This time,
use 3 different size heart cutters to cut out fondant hearts. Set
aside.
Tint some fondant lavender. Roll out to 1/8" thick
and repeat the
process of cutting out hearts.
Mix almond extract and lavender pearl
dust to paint the tops of the cupcakes and some of the hearts. Mix
almond extract and silver lustre dust to add various stripes and polka
dots on some of the hearts.
Have fun creating different designs with
the valentines day cupcakes by layering the smaller hearts on top of
the larger ones. There's no right or wrong way to do it.
Wet the back
of the heart cut outs with a dab of water to make them stick to the
cupcake and to layer them on top of one another.