1. Beat all the cookie dough ingredients on medium speed in a medium mixing bowl until a soft, smooth dough is formed. Shape into a 3/4″ thick disc, wrap well with plastic wrap and chill for 30 minutes or overnight.
2. Preheat the oven to 350°F. Line two baking sheets with parchment paper. Shape the dough into small balls, about the size of a large gumball (a teaspoon cookie scoop. Space evenly on the cookie sheet, leaving about 2″ between cookies. Bake for 7 to 10 minutes.
3. Cool cookies on wire racks. Meanwhile make the glaze by beating all the ingredients together starting with 2 cups confectioners’ sugar and 2 tablespoons heavy cream adding more as needed until it reaches a spreadable consistency.
4. You can pipe the glaze from a piping bag or zip-top bag with a corner cut off or use a spoon to drop a teaspoon of glaze over top of each one and swirl into a circle to cover the tops. Top each one with a red M&M. Store in a tightly covered container up to a week.