I Tre Mercanti" For your dessert head here, they offer some amazing Tiramisù for just 3,5/4,5€ a cup. The place is also a classy gourmet shop but don't feel intimidated, the staff is super friendly and the products eve if they are all top quality are ranged for all kind of budgets. They are on Ponte della Guerra just behind Saint Mark's square (see links and details in the shopping area).