Take a brandy sniffer and put in the freezer. Wait until frozen (3-4 hrs or overnight). Put vodka in freezer to chill, you want it as cold as possible. In a blender half-filled with ice (for each person) add: Blend until ice is chipped, you are looking for a consistency slightly chunkier than a daquiri. Strain into brandy sniffer, add a splash of lemon-lime soda. Serve with a slice of lemon.