Preheat oven to 350 degrees F (170C).
Combine the potato, zucchini, and onion into a large bowl and sprinkle with 1/2 cup flour, salt and pepper to taste. Add the cheese, garlic, mint, and olive oil. Thoroughly mix to coat all slices.
Pour mixture into a greased (olive oil) 11 X 15" baking dish.
Press down on mixture to compact. Carefully pour water over top.
Bake for about 1 hour and 30 minutes or until potatoes are tender. Add a splash more water if mixture looks too dry.
Allow to cool 10 minutes before serving.