In a bowl, mix the minced beef with the cold sweated onion ... and sweat on a gentle heat until soft and pale golden. Slice the canned tomatoes and add, with all the juice, to the onion mixture.

Put the sliced steak on the warm tortillas. Sprinkle with salt and pepper. Top with lettuce, tomato and coriander salsa, guacamole and sour cream. Roll up or fold over and serve hot. Better still ...