Here is the recipe from cathealthcare.com. It does go on to say this is not as good as KMR.
One envelope knox unflavored gelatin should be mixed in 12 oz. boiling water. Then add the following ingredients-
1 egg yolk
1 table spoons light corn syrup
2 tablespoons plain yogurt
2 tablespoons mayonnaise
1 12 oz. can evaporated canned milk
Mix all the contents in a mixer to get dissolved completely. Store it in a refrigerator in a covered bowl. You can keep this stuff for seven days. It adds between 15-20 grams on kittens a day.
This gloop recipe finds it way in saving more than one sick or orphan kitten. I heard wonderous stories from the owners used this recipe for their cats.