Preheat oven to 350°F and line a cookie sheet with parchment paper.
Add the cake mix, eggs and butter to the bowl of your stand mixer and mix together until combined (about 1 minute).
Add the almond extract, then mix, then add the green food color.
Mix until totally combined and there is no streaks of color.
In a small mixing bowl add the powdered sugar and cornstarch and mix with a whisk.
Take a cookie scoop and make a full scoop of the green cookie dough, drop it into the bowl with the powdered sugar.
Using your hands take the sugar coated cookie dough scoop out of the bowl and place on the cookie sheet.
Repeat until you fill the cookie sheet with cookies, 2" apart.
Bake in the oven for about 8 minutes.
Remove and immediately press one large red heart onto the cookie while it is still hot and soft.
Allow to cool a little before transferring to a wire rack to cool completely.
Repeat with the remaining cookie dough.
Notes
Watch the cookies in the oven when it's close to the end of the cooking time. The edges do brown a little but you don't want the cookies to get too brown.