Preheat the oven to 375 degrees, and line baking sheets with parchment.
Cream the butter and sugar, just until smooth and combined.
Mix in the eggs until incorporated one at a time.
Add the flour, cornstarch, and salt, and mix on medium-low speed, until the dough gathers itself into a ball and pulls away cleanly from the sides of the bowl.
Stir in the vanilla.
Divide dough into three parts.
Roll each section of the dough ¼ inch thick between two sheets of parchment paper.
Refrigerate while you do the next section of dough.
When all three parts are finished, take one part of the dough out of the fridge, remove top sheet of parchment and cut out shapes.
Roll the second section, cut out and combine remaining dough from the first section, roll back out between parchment, refrigerate and continue on with 3rd section.
Bake for 9 to 12 minutes.
Cool completely, then roll and cut out fondant hearts.
Spread a small layer of buttercream frosting on each cookie and place the fondant on top.
For the Brushstroke
Mix pink and white gel paste together to form the desired color you like
Use cake decorating brushes to make brush strokes onto the white fondant.
Mix and match colors and use gold dust for another charming touch!