In a medium bowl, combine confectioner's sugar, softened butter, condensed milk, and vanilla extract until well mixed. Refrigerate one hour.

Meanwhile, drain maraschino cherries and lay out onto a cookie sheet. Place in freezer for an hour.

Grab a teaspoon of sugar mixture, and use hands or a rolling pin to flatten into a circle. Place a cherry in the center, then fold sugar mixture around the cherry to form a ball. Set aside, and repeat for remaining cherries. Once all cherries are covered, place back in the freezer.

Fill a small saucepan with 1 - 2" of water. Bring to a boil over medium-high heat. Place a glass bowl on top of the saucepan, creating a double broiler, and add the dark chocolate and whole milk to the bowl. Stir frequently until chocolate is melted. Remove from heat.

Grab the cherries from the freezer, and roll them in the melted chocolate mixture. Once coated, place back on the cookie sheet and freeze one more hour.