Exodus 29:17

29:17 Then you are to cut the ram into pieces and wash the entrails and its legs and put them on its pieces and on its head

Exodus 12:9

12:9 Do not eat it raw ¹  or boiled in water, but roast it over the fire with its head, its legs, and its entrails.

¹ sn This ruling was to prevent their eating it just softened by the fire or partially roasted as differing customs might prescribe or allow.