Potato Gratin - cooking recipe

Ingredients

1 clove garlic, halved
vegetable cooking spray
1 c. chopped onion
6 medium-size baking potatoes, peeled and cut into 1/8-inch slices (about 2 1/2 lb.)
1/4 tsp. salt
1/4 tsp. freshly ground pepper
3/4 c. (3 oz.) shredded extra-sharp Cheddar cheese
1/4 c. grated fresh Romano cheese
1 3/4 c. low-sodium chicken broth
1 c. evaporated skimmed milk

Preparation

Rub a shallow 3-quart baking dish with cut sides of garlic halves; discard garlic.
Coat dish with cooking spray.