Cook the meat (I used cecina, but you can use steak or ground beef). Season to taste and cut into medium-sized pieces.

Cook the chorizo until very crispy. Once done, drain and remove it from the pan. In the same pan, add the onion and sauté until soft and golden (it will pick up the color from the chorizo).

Cut a piece of aluminum foil and shape it like a shallow bowl by folding up the edges. Spread butter on the bottom, then add a layer of mashed potatoes, the meat, yellow cheese, Oaxaca cheese, and chorizo to make a choriqueso-style filling. Place it in a skillet with a lid so the cheese melts, and it's ready to serve.