So i started not so long ago and have constantly needed to go down a rabbit hole, just to find a specific ingredient to get every recipe both simple and complex, god forbid i want some salt on my pretzel, and will now put putting all of that knowledge here for everybody, but mostly myself so i know where to look, this will be updated as i find new easy ways to get different ingredients.

All fish: as far as I'm aware all fish are found in the fishing profession minigame and how to get them is simply dependent on level as some fish are specific to specific areas you unlock, so simply grinding up those levels is probably the best bet for anybody else who wants easy food

Milk: milk has given me so much grief, so i will simply say this, for anybody else who wants to get all the recipes, do not wait for the mole to bless you, just grind up the cooking skill to 20 so that you can unlock goldsea's finding ingredient event that can happen in the camp area, in the mean time simply do other recipes, as far as I'm aware no enemy drops milk before then and the only other way to get milk is the mole market (i have not had this happen to me once since starting) or maybe a other player who is feeling generous and selling it on the flea market (i have also not seen this happen either but it might one day)

Meat: mind you this simply applies to all meat that has basically the same cooked result besides bug meat which is just a different color, and fatty meat which makes bacon, unlike fish there are a few areas to get meat consistently, bug meat can be reaaally easily gotten from the enemies in darkspires "the neck" area, i think it also drops from other enemies but less commonly, most mammal enemies drop meat too, some reptile and amphibious ones too, and lastly is hunting and a fair few different hunts give both normal raw meat and fatty meat, and honestly hunting is a much easier way to get fatty meat, at least for me that is.