- Preheat oven to 425°F.
- Halve or quarter potatoes lengthwise into bite-size pieces.
- Place them in 13 x 9-inch gratin dish or shallow baking dish, and add garlic, oil and rosemary, and salt and pepper to taste; don’t under salt potatoes or they’ll taste flat.
- Sprinkle water or broth over potatoes, then spread evenly in dish.
- Cover dish with lid or foil, leaving a gap so steam can escape.
- Place dish on center oven rack, and cook potatoes for 15 minutes.
- Remove covering, and stir potatoes.
- Bake, until they test done when pierced with a paring knife, about 15 minutes.
- Remove from oven, and sprinkle 1 teaspoon of balsamic vinegar over potatoes, stirring to coat.
- Serve hot.
- Add 1 small onion, halved and thinly sliced, to the potatoes and cook as directed.