1-Add the butter, sugar, egg, and vanilla: Add the butter, sugar, egg, and vanilla extract to a large mixing bowl and beat with an electric mixer until creamy.
2-Scrape the sides of the bowl with: Scrape the sides of the bowl with a rubber spatula and add the flour and salt to the mixing bowl. Mix slowly until the cookie dough comes together.
3-Separate about 1 ¾ cups of cookie: Separate about 1 ¾ cups of cookie dough into a separate bowl and set aside for later.
4-Add a few drops of pink or: Add a few drops of pink or red food coloring to the remaining cookie dough and mix until the color is fully incorporated.
5-Form the dyed dough into a disk: Form the dyed dough into a disk shape, wrap it with plastic wrap, and place it in the refrigerator for at least one hour.
6-Remove the dough from the refrigerator and: Remove the dough from the refrigerator and place it on a lightly floured surface. Roll the dough out until it is ¼ inch thick.
7-Cut out cookies with a 2-inch, heart-shaped: Cut out cookies with a 2-inch, heart-shaped cookie cutter until all the pink dough is used up.
8-Stack the cookies on top of one: Stack the cookies on top of one another and compress them gently so they all stick together.
9-Roll small sections of the undyed dough: Roll small sections of the undyed dough between your hands and press the strips around all sides of the stacked hearts until no pink is showing.
10-Roll the dough log gently back and: Roll the dough log gently back and forth to smooth it out, wrap it in plastic wrap, and place it in the refrigerator for a minimum of four hours or overnight.
11-Preheat the oven to 350 degrees Fahrenheit: Preheat the oven to 350 degrees Fahrenheit when ready to bake the cookies.
12-Remove the chilled cookie dough from the: Remove the chilled cookie dough from the refrigerator and slice it into cookies that are about ⅓ inch thick.
13-Roll the edges of the cookies in: Roll the edges of the cookies in the sugar sprinkles if desired. I did half of mine with sprinkles and half without.
14-Place 8 of them, evenly spaced, on: Place 8 of them, evenly spaced, on a baking sheet and bake for 10-11 minutes, or until the edges are LIGHTLY golden brown.
15-Allow the cookies to rest on the: Allow the cookies to rest on the baking sheet for a few minutes before transferring them to a wire cooling rack to cool completely.
16-Repeat until all the cookies are baked: Repeat until all the cookies are baked. Store any leftover cookies in an airtight container for up to three days.