Clarita's Lamb-Kidney Egg Omelet (here 'tortilla' means a Spanish egg omelet, not a maize flatbread)

Ingredients

• 12 eggs
• butter
• lamb kidneys (riñones de cordero)
• fine herbs (hierbas finas)
• 4 tablespoons roast-meat juice (jugo de carne asada)
• 1/2 glass sherry wine (vino Jerez)
• pepper
• salt
• spicy sauce for serving

Instructions

1. Beat twelve eggs to a froth; pour half into a buttered pan and cook as an omelet over moderate heat, turning to cook evenly.
2. Cut lamb kidneys into small pieces and cook in butter with finely chopped fine herbs, four tablespoons of roast-meat juice, and half a glass of sherry; season with pepper and salt.
3. Spread the filling over the omelet, pour the remaining beaten egg over it, add a piece of butter, and cover the pan with its lid topped with embers and coals.
4. When cooked, serve with a spicy sauce of mustard, or tomatoes with green ají.