Place a small amount of white vanilla frosting on a plate. Dip the rim of a chilled martini or coupe glass into the frosting, then roll it in holiday sprinkles until the rim is fully coated. Set the glass aside.
2 tbsps (30 g) vanilla frosting, 3 tbsps (36 g) holiday red and green nonpareils
Fill a cocktail shaker with ice. Add the vanilla vodka, Irish cream, amaretto, and heavy cream. Shake vigorously for 20 to 30 seconds, or until the mixture is well chilled and lightly frothy. Shaking cream-based cocktails aerates the mixture and creates the smooth, dessert-like texture this drink is known for.
ice, 2 oz (60 ml) vanilla vodka , 2 oz (60 ml) Irish Cream, 1 oz (30 ml) Amaretto, 1 oz (30 ml) heavy cream
Strain the martini into the prepared glass and serve immediately while the top is still velvety and the rim is intact.
Notes
Chilled glasses hold the froth longer and keep the drink creamy.
Warm frosting makes coating the rim easier.
If you prefer a thinner texture, sub heavy cream for half and half, but you will mouthfeel.