With a pestle, crush the red pepper in a mortar. In a bowl, mix it with the onion, tarragon, egg, breadcrumbs, mustard, Parmesan, nutmeg, and beef. Shape the mixture into four patties and refrigerate for half an hour to firm up slightly.

When cooking the hamburgers, heat a frying pan or grill. Brush the pan with a little oil, season the patties generously with salt and pepper, and cook for 10 minutes, turning carefully every minute, until they are tender, pink, and juicy, or longer, to taste. Be careful not to break them when turning.

Meanwhile, coarsely chop the lettuce, tomato, and cucumber, mix and set aside. Once the patties are cooked, slice the ciabatta bread in half and grill quickly on the grill or in a toaster. Assemble the grilled bread and serve on individual plates with pickles and salad (add a little extra virgin olive oil or vinaigrette of your choice) on the side.