This is a take on the Bellini, a peach-infused champagne drink made famous by Harry's Bar at the Hotel Cipriani in Venice, Italy. White nectarines are sweet and ambrosial, the perfect partner for a glass of bubbly. If you don't have peach liqueur, add a tablespoon or two of sugar in its place.
Place the nectarines, peach liqueur, and lemon juice in a blender and process until completely smooth. Strain through a fine mesh strainer and transfer the puree to a large glass pitcher. Refrigerate until completely chilled.
To serve, carefully add the champagne to the pitcher, stirring gently to blend. Alternately, pour 2 tablespoons of puree into individual champagne flutes and top with sparkling wine.