To Prepare the Cookies

1. Preheat the oven to 350 degrees. Line two cookie sheets with parchment paper. Pour the sprinkles into a small bowl and set aside.
2. In the bowl of a stand mixer, cream together the butter, powdered sugar and vanilla for about 2-3 minutes, until light and fluffy. Add salt and mix until just combined. Gradually add the flour (about ½ cup at a time) mixing well after each addition until completely incorporated and the dough stays in a ball when pressed together.
3. Using a measuring tablespoon, scoop the dough out into even portions. Using your hands, roll each portion into a round ball and then roll the dough in the sprinkles, pressing down as needed to make the sprinkles coat the cookie dough. Place the balls onto the prepared cookie sheet about 1½ inches apart. Using your thumb, gently press down on the top of each ball and make a small indentation, being careful not to crack the dough. (Do not completely flatten the dough – it will flatten a bit as it bakes.)
4. Bake the cookies for 10 minutes. Remove from the oven and using a melon baller or other small round kitchen tool, gently press on each cookie to make a deeper indentation (but be careful again, not to press too hard and crack the sides). Bake for 7-8 minutes more until the cookies are set.
5. Cool the cookies completely on a wire rack before frosting.

To Make the Icing

1. In a small bowl, combine the powdered sugar, corn syrup, vanilla extract, melted butter and 1 tablespoon of milk. Stir to combine and add more milk as needed to get a smooth and spoonable, but not runny, consistency.
2. If you want to make different colored icings for your cookies, divide the icing into small bowls – one for each color of icing you desire. Dip a toothpick into the gel food coloring and then stir into your icing, adding more as needed to make the color you want. With a clean toothpick, repeat the process for the other colors.
3. Spoon a small amount of icing into the center of each cookie and allow to set completely before serving.