I only know a syllabub as a drink-- something akin to a egg nog-- I have some recipes for some-- but they don't really sound good-- one of those things i'd be glad to try if you made it-- but One syllabub "sheeps wool" is a blend of alcohol, whipped cream, milk, and apple sause-- not all bad-- it could with some modification be come a "smoothy"
I once milked a cow (being a real city person, i actually paid for the privledge to do so*...) the milk, as it squirts out, froths up in the pail-- and since syllabubs are frothy, dairy based drinks...
*i have also paid for the chance to walk behind a plow horse, and try to make a straight furrow...