Butter.
This was curdled milk. Genesis 18:8; Deuteronomy 32:14. Jael brought Sisera 'butter' to drink, Judges 5:25; and Job in Job 29:6 speaks of his steps being washed with butter when the Almighty was with him in prosperity. The promised land was to flow with milk and honey: cf. Job 20:17. Curdled milk is a common beverage in the East, and when mixed with honey is very agreeable.