Bake potatoes at 400° for one hour on until done; cool. Cut potatoes in half lengthwise; scoop out pulp and reserve. Discard shells.
Melt butter in a Dutch oven over low heat. Whisk in flour until smooth. Cook one minute, stirring constantly. Gradually whisk in milk; cook over medium heat 10 minutes, whisking constantly, until mixture is thickened and bubbly.
Stir in potato pulp and green onions; bring to a boil. Cover, reduce heat and simmer 10 minutes. Add bacon and next 4 ingredients; stir until cheese melts. Garnish, if desired. Serve immediately.