Scrub potatoes with a vegetable brush; pat dry. Prick potatoes with a fork. Bake in a 425 degree F oven for 40 to 60 minutes or until tender; cool. Peel potatoes, if desired. Chop potatoes; set aside.

In a heavy large saucepan or Dutch oven, melt butter over medium heat. Add onion and celery. Cook and stir about 5 minutes or until crisp-tender. Stir in flour, thyme, salt and pepper. Add half-and-half or milk all at once. Cook and stir for 5 to 6 minutes or until thickened and bubbly. Add potatoes, 1 cup of the cheese, and the broth; stir until cheese melts. Slightly mash potatoes with the back of a spoon or a potato masher.

For the topping, reserve 2 tablespoons of the bacon. Stir the remaining bacon and 1 tablespoon of the green onion into soup. Heat through.

To serve, top each serving with reserved bacon, remaining 1/4 cup cheese, green onions and the sour cream. Makes 6 servings (about 1 cup each).