Home-made suet cakes,, yum! Melt one lb. beef suet, strain out the crackling (starlings and squirrels love it), cool, then melt/strain/cool twice more. Melt once more and mix in stuff as desired: this batch has peanut butter, unsalted dry-roasted peanuts, corn meal, oatmeal, and currants left over from a baking experiment. Add the extra ingredients until it’s a fairly thick mixture, between cake batter and cookie dough in consistency. Pour it into pans to about 1 or 1.5″ thickness (or whatever works in your suet feeder) and cool again. After it’s cooled, you can slice it into hunks and freeze it.
I put one of the quarters above in my feeder and it was GONE in less than 2 days. The birds were literally lining up to get at it.