1 pound powdered sugar
3 tablespoons butter, softened
2 1/2 teaspoons peppermint extract
1/2 teaspoon vanilla extract
1/4 cup evaporated milk
2 cups (12 ounces) semisweet chocolate chips
2 tablespoons vegetable shortening

In a bowl, combine powdered sugar, butter, and flavorings. Add milk and blend well. Roll into 1-inch balls and place on a waxed paper-lined cookie sheet. Chill for 20 minutes. Flatten with a glass to 1/4 inch thickeness; chill for 30 minutes. In double boiler or microwave-safe bowl, melt chocolate chips and shortening. Dip patties in the chocolate; place on waxed paper to harden and freeze for a short while.
Makes about 50 to 60.

Source: http://southernfood.about.com/od/candyrecipes