When I worked for L.A. County in Canoga Park, I used to visit Fina Estampa Peruvian restaurant weekly. Their lunch special included an appetizer (usually this dish), an entree and a drink for about $7 bucks. I have been trying to mimic their Papas for 6 years! I think I have finally found it! I had to send away for the aji, but if you have a Latin market, you should be able to find it. This makes 2 batches of sauce, use one now, save one for later, or if you are feeding a crowd, double the potatoes.