Bake potatoes until tender; cool. Scoop out pulp into a small bowl and break up into pea-sized pieces.
Melt butter in a heavy saucepan over low heat; stir in flour. Cook for 1 minute, stirring constantly. Add the milk gradually.
Cook over medium heat until thickened and bubbly, stirring regularly. Season with salt and pepper.
Add the potato pulp, 2 tablespoons green onions, 1/2 cup of the bacon, and 1 cup of the cheese. Cook till heated through.