1607 T. Dekker & J. Webster v. i Some burnt Sack for her good wenches: or possit drink.
1747 J. Wesley 51 Drink..a quarter of a pint of Allum Posset-drink.
1999 (Nexis) 2 Oct. 6 Cream and curds were widely used in the medieval kitchen and hot ‘posset’ drinks made with milk curdled by ale were very popular.