Ideally, a hypoallergenic diet should be composed of hydrolyzed protein which isn't something you can home cook. You could, however, see if a novel protein diet is of value. Venison or rabbit is usually the primary protein source, however, and those are expensive meats. I do have a pork and barley recipe but I must admit I don't know how palatable that would be to Butters:
pork loin, broiled, 5 ounces
barley, pearled, cooked, 1/2 cup
canola oil, 1 tsp
salt substitute (potassium chloride), 1/8 tsp
salt, iodized (sodium chloride), 1/8 tsp
bone meal powder, 3/4 tsp
multivitamin & mineral tablet, kids complete, 1/2 each
vitamin K, 100 mcg vitamin K per tablet, 1 tablet
taurine powder, 1000mg per 1/4 tsp
Provides 419 kcal, the daily requirement of a 19lb cat. Uneaten food can be refrigerated for 3 days or frozen indefinitely while checking for spoilage.
The positive response to a food trial may be rapid or not seen for 8-12 weeks. Please continue our conversation if you wish.