Preheat oven to 350 degrees. Beat butter with sugar, egg and vanilla in a large bowl. In another bowl, combine flour, baking soda and salt. Add dry mixture and milk to the butter and sugar mixture, mixing until well blended.
Shape the dough into 1 inch balls.
Roll the balls in the red and green sugar.
Bake at 350 degrees on a greased cookie sheet for 8-10 minutes.
Remove from the oven and let cool for 2-3 minutes. Place an unwrapped Peppermint Bark Bell in the center of each cookie and push it into place.
Place cookies on a cooling rack and allow cookie to cool completely before serving.
Calories: 136kcal | Carbohydrates: 20g | Protein: 2g | Fat: 6g | Saturated Fat: 3g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 1g | Trans Fat: 1g | Cholesterol: 19mg | Sodium: 80mg | Potassium: 18mg | Fiber: 1g | Sugar: 12g | Vitamin A: 136IU | Calcium: 15mg | Iron: 1mg