1 drop Angostura Bitters
1 sugar cube
1 splash Campari
First, add the bitters to the cube and place in the bottom of your favorite Champagne flute. Add a splash of Campari, and then fill it up with Champagne.
Angostura Bitters are a specific type of bitters with a very unique flavor. Make sure you only use a drop, it will make a difference! Most liquor stores should carry this product.