01 -
Preheat the oven to 350°F and prepare a small baking sheet with parchment paper or a silicone mat
02 -
Mix melted butter, sugar, egg yolk, vanilla extract and red food coloring until well combined
03 -
Gently sprinkle flour, cocoa powder, baking soda and salt over the wet mixture, stirring just until combined
04 -
Spread dough evenly in bowl and split in half, aiming for 3 cookies from each half
05 -
Form dough balls, roll in extra granulated sugar, and place on baking sheet with space between them
06 -
Bake 10-12 minutes until cookies spread, crackle and look dry on top
07 -
Let cookies sit on baking sheet for 2 minutes, then move to wire rack
08 -
After 10 minutes of cooling, press a chocolate heart into each cookie center and refrigerate 30 minutes to set
09 -
Bring cookies to room temperature before enjoying