Step 1

Preheat the oven to 375 degrees F and line baking sheets with parchment paper.

Step 2

Place the butter, cream cheese, and sugar in a large mixing bowl and beat on medium-low speed until smooth (about 1 minute).

Step 3

Add the egg yolk, vanilla, and food coloring and mix on medium speed until combined.

Step 4

Scrape the bottom and sides of the bowl with a silicone spatula, then add the flour, cocoa, cornstarch, and salt.

Step 5

Mix on medium-low speed until a stiff dough forms (about 30 seconds to 1 minute). The dough should gather itself into a ball and come cleanly away from the sides of the bowl. If the dough seems too sticky, try mixing in a little more flour.

Step 6

Roll the dough to 3/16-inch thick (rolling pin rings ensure an even and exact thickness) between 2 sheets of parchment paper.

Step 7

Remove the top sheet of parchment, and cut shapes with a 3-inch heart cookie cutter.

Step 8

Peel the shapes from the bottom layer of parchment, and transfer to the prepared baking sheets.

Step 9

Bake for 12 to 16 minutes, or until set around the edges but still a little soft towards the center.

Step 10

Cool completely, then frost with royal icing.