4 drops Angostura bitters 4 sugar cubes 1 1/2 cups demi-sec sparkling wine (such as Gruet), chilled 1/2 cup cognac, chilled

Place 1 drop of bitters onto each sugar cube; place 1 sugar cube into bottom of each of 4 Champagne flutes. Combine wine and cognac. Pour 1/2 cup wine mixture into each flute.