You can be generous with the salt and pepper seasoning in this recipe. Fresh mozzarella cheese does not have much of a flavor on its own and needs seasoning.
I usually serve this on a platter and garnish with whole basil leaves. I serve the sauce separate so if you have any tomato/cheese slices left over, you can just cover it with plastic wrap and put it in the fridge for the next day.
Mix the balsamic vinegar and olive oil in equal parts, then adjust from there to your taste.
Makes a great summer salad on a hot day.