Grease your cookie sheets with non stick cooking spray or butter. Or, line with parchment paper.
Preheat oven to 350 degrees.
Add 1 cup of butter and .25 cup of sugar to the mixing bowl. Mix at medium high speed for 2 - 3 minutes to cream them together. It should be smooth, light and fluffy.
Add 1 egg, 3 tablespoons of milk and 2 teaspoons of vanilla to the mixing bowl. Mix on medium speed for a minute or until well combined.
Turn the mixer on low and slowly add in 2.5 cups of flour and .5 teaspoon of salt. Scrape down the sides of the bowl as needed. Mix until smooth and well combined.
Transfer the dough into the piping bag with the large star tip on the end.
Pipe the dough into small circular spirals onto the baking sheet and then place in the freezer to chill for 10 minutes.
Remove from the freezer and bake for 10 - 12 minutes or until edges are firm.
Remove from the oven and allow to completely cool (around 10 minutes).
While cookies are cooking, melt the chocolate for dipping. Place .5 cup of semi sweet chocolate chips in a bowl and heat in the microwave at 30 second intervals until just melted and smooth.
Repeat above step with .5 cup of white chocolate chips.
Dip cookies into the melted chocolate, just half of the cookie should be dipped. Make sure to remove any excess before laying the cookie back down.
Sprinkle holiday sprinkles onto the chocolate before it dries.
Make sure chocolate completely dries and hardens before moving cookies.