If someone wants to feed their pet a homemade diet all the time, they need to make sure it's complete and balanced or their pet will get sick from nutritional deficiencies. It's not very hard but you do need to be attentive to what nutrients your pet is getting. Check out our raw and homecooked subforum for a lot of info about that!
As for treats, that's just anything the kitty enjoys. Tiny bits of cheese or meat seem to be appreciated the most, no real recipe needed. Even with storebought treats, the ones kitties seem to like best are the freeze-dried bits of real liver or chicken.
Yes, please check out these threads about making home-made raw or cooked food for your kitties. There are "recipes" on those threads. If the home-made food or treats are less than 15% of their total diet, then you don't need to worry about balancing it. You can feed some healthy meat treats a few times a week.