Place a sugar cube on a cocktail napkin and add 3-4 dashes of Angostura bitters to soak the cube.
Add sugar cube to Champagne flute.
Add Cognac to glass.
Fill glass with 3-4 ounces of Dry Champagne or until appropriately full.
Express the lemon twist over the rim of the glass and discard.
Notes
Ensure you chill the Cognac before adding, otherwise warm Cognac can 'kill' the drink and make it flat.You can experiment with the sugar cubes and use a Demerara sugar cube if you like.