1Pierce potatoes with fork. Arrange potatoes about 1 inch apart in circle on microwavable paper towel in microwave oven. Microwave uncovered on High 8 to 10 minutes or until tender. (Or bake potatoes in 375º oven 1 to 1 1/2 hours.) Let potatoes stand until cool enough to handle.
2While potatoes are cooking, spray 4-quart Dutch oven with cooking spray; heat over medium-high heat. Cook mushrooms in Dutch oven 1 minute, stirring frequently; reduce heat to medium. Cover and cook 3 minutes; remove from heat. Stir in ham, green onions and red pepper. Cover and let stand 4 minutes.
3Split baked potatoes lengthwise in half; fluff with fork. Spread 1 tablespoon of the sour cream over each potato half. Top with ham mixture and cheese.