Preheat the oven to 375 degrees. Line a baking sheet with parchment paper.
Cream the butter and sugar with an electric mixer in a large bowl.
Add in the eggs, vanilla, and food coloring, until the desired color.
Mix in the baking soda and add in the flour 1/2 a cup at a time.
Roll the dough out, until the dough is 1/8 inch thick. From there, cut the cookies out with a heart shaped cookie cutter.
Put the cookies on a baking sheet 2-inches apart.
Cook in the oven for 7-9 minutes or until the cookies are golden brown, on parchment paper.
Mix together the powdered sugar, milk, and vanilla extract until the desired consistency, to make the glaze.
Add a few drops of red food coloring, and swirl with a toothpick or spoon a few times, until the colors become tie-die. Make sure you do not over-swirl, or the cookies will not have a marbled effect.
Take a cooled cookie, and dip it into the glaze, and take it out and put it back out on a plate. As you dip the cookies, you may have to swirl more food coloring.
Serve when the glaze hardens, as a delicious valentines day treat!
