syllabub

noun3

1. •
   A drink dating back to the 16th century consisting primarily of milk curdled with an alcoholic beverage or some acid such as lemon juice, which is usually then sweetened and spiced.

   • In the evening I shall hope for the honour of your Lordship's company to take a dish of tea there, or a sullabub warm from the cow. — 1766
2. •
   A dessert pudding derived from the drink.

   • "Oh, I do dote on custard," remarks Mrs. Goram, with a mincing smirk, "it is such an improvement to a tart." / "I dote on syllabub," interposed Miss Jemima, sentimentally. — 1873
3. •
   (figurative, old-fashioned) Something lacking substance; something frothy, insubstantial, or lightweight.