Amaretto Cherry Fizz

This is a simple addition to a classic dish. In the Amaretto Sour cocktail, the nutty sweetness of Amaretto liqueur is combined with the astringency of lemon and the cloud-like foam of whipped egg white. In this version, the amaretto is filled with cherries and enlivened with a drop of prosecco (sparkling Italian wine).
Place fresh cherries in a glass container or jar; pour over the amaretto cherries. Cover, shake gently and let stand in a cool, dry place for at least 48 hours or up to 2 weeks.Strain the cherries through a fine sieve into a bowl, reserving the amaretto and cherries.Pour the amaretto into a large cocktail shaker or quart-sized glass jar. Add lemon juice and egg whites. Add as much ice as possible, cover and shake vigorously for 15 seconds. Pour about 1/4 cup into each of 8 chilled cocktail coupes or champagne glasses; sprinkle each serving with 1/4 cup of prosecco. If desired, garnish with cherries soaked in "amaretto". Serve immediately.