Peel the potatoes and cut (slightly thicker than frying), put in a baking dish and put the olive oil, salt, balsamic vinegar and mix well with hands on top, sprinkle with thyme (optional can be put and 2-3 cloves garlic, peeled not), put it and the water, taking care not to wash the spices. Bake at 250C until crusted and water evaporates completely.