In case anyone wasn't sure, the new Gather Ingredients encounter drops 2 random ingredients and they are mostly filled with the ingredients you need for the recently added recipes. Just off the top of my head, I've gotten chili peppers, yoghurt, salt, pepper and milk from the encounter so far.
If you are level 20 cooking, you can go grind in Goldsea 1 (that's the den area, NOT the swords!) for them. Very helpful if you are struggling with feeding the farmers for the current event!