Chicken Fat Heaven

This was a new one to me. I was at Zern's, a combination farmers' and flea market right off of route 100 in Gilbertsville, PA (NW of Philadelphia). There was a big long line for (I thought) rotisserie chickens because I could see them through the crowd. Then I noticed most of the customers walking away from the stand with styrofoam cups and forks. I got in line and after about a 10 minute wait, saw the attraction. They had two big electric frying pans filled with bubbling chicken fat from the bottom of the rotisseries. In one was chicken livers; in the other, fresh PA button mushrooms. I got a "half and half" and what an incredible taste sensation. Of course, I regretted it about an hour later as pure chicken fat pumped through my arteries. Have you ever seen this done at any rotisserie chicken places?