Start by garnishing the rims of 3 glasses with vanilla frosting and crushed peppermint candies.
Chill the glasses in the freezer while you make the milkshakes.
Combine the eggnog and pink peppermint ice cream in a blender and blend on high. For a stronger peppermint flavor, add 1 teaspoon peppermint extract. Divide the mixture between the prepared glasses and garnish with peppermint candy bark, whipped cream and more crushed peppermint candies.