Heat a pan on the stove and add the lamb. If your lamb has some fat on it, please do not cut it off. Allow the meat to slowly brown and the fat to render out. If your lamb is very lean, add some olive oil to the pan and brown slightly. Remove from the pan and add the sliced onions. Sauté the onions until it has a caramel colour. Add the balsamic vinegar and sugar, if using, and cook until it becomes sticky. Remove and keep to one side. If you are using cherry tomatoes, halve them and place them into the same pan. Allow to just warm through, without losing their texture.

It is time to assemble your sandwich. Slice the ciabatta and butter lightly. Pile with lettuce, tomatoes, slices of lamb and finally top off with those über-delicious onions. Drizzle with some balsamic vinegar.