Preheat oven to 400 degrees F. Coat large, shallow baking dish with cooking spray. Baking dish should be large enough to hold onion halves.

Trim about 1/4 inch off top and bottom of onions so that halves sit flat on a plate. Cut onions in half cross-wise and then peel them. Arrange onion halves, cut sides up, in baking dish.

Brush exposed onion tops with olive oil and sprinkle with salt and pepper. Bake about 35 minutes.

In glass measuring cup, mix beef broth and soy sauce. Remove dish from oven and pour sauce over onions. Return to oven and continue baking about 1 hour, basting occasionally. If liquid evaporates, add a little water.

Remove dish from oven and sprinkle cheese and sage evenly over onions. Bake 5 to 7 minutes more or until cheese melts.