Cut the zucchini in half lengthwise
Using a small spoon scoop out the zucchini flesh, leaving a small ridge to make the zucchini boat
Chop the scooped zucchini into small pieces
Heat the olive oil in a frying pan and gently saute the chopped zucchini for 5 minutes until cooked
Mix the ricotta, Parmesan, lemon zest and basil in a bowl. Season
Add the cooked zucchini and mix well.
Spoon the ricotta mixture into the zucchini shells.
Slather the tomato sauce on the bottom of a baking dish (if using the tomato sauce. If not, grease it with butter)
Place the zucchini boats in the baking dish.
Sprinkle the mozzarella cheese over the zucchini boats
Bake at 200C/400F degrees for 35-40 minutes until golden.