1/2 oz. lemon juice
1/2 oz. simple syrup (sugar* and water mixed in equal parts)
1 1/2 oz. booze (Some people make it with gin, other people make it with cognac. It's traditional and therefore more correct to make it with gin, but certain cable television news hosts prefer it with cognac.)
Shake that up with ice.
Strain into a champagne glass
Top with champagne.
*Rachel explained that her simple syrup was brown because it's Demerara syrup. Demerara sugar is raw sugar that hasn't had the molasses refined out of it. Kind of like that sugar that comes in the brown paper packets (but different).