It's from Morton's, the steakhouse people, and is available at special times during the year, notably Valentines and Mother's Days. Here's the recipe so you can sip it any time.
The Red Velvet
2 oz. Lindeman's Raspberry Lambic
4 oz. Prosecco
.5 oz. chambord
1 lemon peel
In a mixing glass stir in liquid ingredients with 2 ounces of ice for 5 seconds. Strain into a champagne flute. Squeeze lemon peel over glass and garnish with a fresh raspberry on a pick. And yes, the drink should have a foam cap.