Steam the cauliﬂower ﬂorets for 7 minutes, or until almost cooked but still slightly crisp.
Meanwhile, whisk the olive oil with the garlic, vinegar, parsley, shallot, salt, pepper and sugar. While the cauliﬂower is still hot, put it in a bowl and pour on the dressing, gently turning the ﬂorets until they are evenly coated. Leave to cool.
Mix the chopped tomatoes with the mayonnaise, tomato sauce, Tabasco sauce and lemon juice and season to taste.
Arrange a layer of lettuce leaves on a ﬂat serving plate, put a layer of cauliﬂower on top and spoon on a little of the tomato mayonnaise. Continue to layer in this way with the lettuce, cauliﬂower and mayonnaise to make a pyramid shape, concealing the lettuce. Finish with a layer of cauliﬂower. Spoon over any remaining mayonnaise, then sprinkle with the shreds of cucumber and capsicum and the capers. Serve at once.