Choose a new cookbook worth up to £28 when you subscribe to our magazine.
Heat a large frying pan. Spread the membrillo paste over one slice of bread (you might need to mash it first with 1 tsp water if it’s very firm), top with the chorizo and cheese, and sandwich with the other slice. Spread the outside of both pieces of bread with mayo, and press on the sage leaves.
Heat the oil in the pan and cook the toastie for 2-3 mins each side, squashing with a fish slice every now and then, until the bread is crisp and golden and the cheese has melted. Cut in half to serve.