1/2 cup whole or lowfat buttermilk
1 Tbsp. honey
1 pint vanilla bean ice cream, softened until just starting to melt at its edges
1 pint lemon sorbet, softened same way
In a blender, combine the buttermilk and the honey. Blend for 15 seconds. Add the ice cream and the sorbet, then pulse several times to begin breaking them up. With the blender off, use a silicone spatula to mash the mix onto the blades.
Continue pulsing and stopping to mash until the mixture is smooth and easily moves around in the blender, about 1 minute.