Preheat oven to 350°.
Pierce potatoes with a fork; arrange on paper towels in microwave oven. Microwave at HIGH 6 minutes or until tender. Let stand 5 minutes. Cut each potato in half; scoop out pulp, reserving shells. Combine potato pulp, onions, and remaining ingredients with a mixer at medium speed.
Spoon potato mixture into shells. Place on a baking sheet; bake at 350° for 10 minutes or until thoroughly heated.