Preheat oven to 350 degrees.
Cream together butter, sugar, vanilla, and milk in a large bowl. Then add in egg.
In a separate bowl, sift together flour, baking soda, and salt. Then add to the butter mixture.
Add 1/4 cup of sugar to two separate small bowls and then add a few drops of red food coloring to one bowl and a few drops of green food coloring to the other.
Mix the sugar and food coloring so that you have red sugar and green sugar.
You can just choose one color if you prefer. Or just plain white granulated sugar if you don't have food coloring.
Roll the dough into 1-inch balls and then roll half of the dough balls in the red colored sugar and the other half in the green colored sugar.
Then place them on a cookie sheet lined with silicone baking mats or parchment paper.
Bake at 350 for 8-10 minutes.
While the cookies are baking unwrap all the Hershey kisses and set them aside.
After the cookies are done baking, remove them from the oven and place them on wire cooling racks.
Let them cool for a few minutes, then press a kiss on top of each cookie.