In an old-fashioned glass, pour in 3 to 4 ounces of Italian Prosecco, or to your taste. You also can use any sparkling wine you may have around the house. It’s a very forgiving recipe. Gently add 1-by-1-inch ice cubes with tongs to keep the wine from losing bubbles. Add Chartreuse, gently stir once, and serve. Makes one cocktail.