1/2 cup olive oil
1 (3-inch) slice of fat from highquality cured ham like Iberico, (Available at supermarkets) Serrano or prosciutto di Parma, chopped into small pieces, optional
1 red bell pepper, sliced
2 tablespoons tomato concentrate or tomato paste
1/2 cup homemade or store-bought demi-glace, optional
Salt and freshly ground black pepper
Finely chopped parsley, for garnish
Roasted potatoes and crusty bread, for serving
In a large pan, place the bulls tails single layer, standing upright. Press a couple of saffron threads into the top of each tail. Add chopped vegetables and 1 bottle of red wine, or more if needed to cover all the ingredients. Leave in the refrigerator for 24 hours.
Remove the bulls tails or oxtails and set aside. Strain the vegetables and keep the liquid and the strained vegetables. In a deep pan heat the olive oil over medium/high heat. Add fat, if using, and render down. Add the strained vegetables and sauté until lightly caramelized, about 10 minutes. Add the caramelize all the ingredients together for 15 minutes longer.
Add the tails one by one, stand them upright and move aside the caramelized vegetables so that the tails contact the bottom of the pan. Turn them over and repeat on other side. Add marinade and barely cover the bulls tails. If needed, top up the liquid with water. Add tomato concentrate. Cook over a slow, low heat until the meat from the tails is falling off the bone.
Serve the stew immediately, garnished with finely chopped parsley, accompanied by roasted potatoes and crusty bread. This stew can also be made a day ahead and reheated to serve the following day.