Switch it up
If you like the combo of lettuce, avocado and tomato, lots of other ingredients go well with these flavours. Try skinless chicken, lean roast beef or Atlantic prawns.For a veggie version of this sandwich, spread the bread with houmous, then thinly slice the avocado and use it instead of the prosciutto.
First, cook the prosciutto. Heat a non-stick pan, add the slices in a single layer without oil and cook for a few mins each side until they are starting to crisp.
Meanwhile, stone the avocado and scoop the flesh into a bowl. Roughly mash, then spread on the bread. Top two slices of the bread with the tomato, some prosciutto, the lettuce and the rest of the prosciutto. Sandwich with the remaining bread and halve to serve. You can keep the sandwich together with a cocktail stick.