This is a variation on the classic French 75 cocktail.
Follow my simple syrup recipe. Chill the simple syrup. I suggest doing this a few hours to a day ahead of time.
Puree about 1 1/2 cups of frozen or fresh strawberries (so you have enough for several cocktails).
Chill a cocktail shaker for about 15 minutes
Add vodka, strawberry puree and simple syrup to a cocktail shaker filled with ice. Shake vigorously and strain into a glass. I used a stemless champagne class from CB2.
Add approximately 3 ounces of prosecco.