Heat oven to 350F and bake the potatoes until fork tender, about 1 hour to 1 hour 15 minutes. (You can bake the potatoes beforehand).
Melt butter in a medium saucepan. Slowly blend in flour with a wire whisk until thoroughly blended. Cook the roux (flour in butter) until a very pale golden. Gradually add milk to the roux, garlic and season to taste, whisking constantly.
Cut potatoes in half, scoop out the interior and set aside. Chop up half the potato peels and discard the remainder.
When milk mixture is very hot, whisk in potato. Add green onion and potato peels. Whisk well, add sour cream and crumbled bacon. Heat thoroughly. Add cheese a little at a time until all is melted in .
Note: You can set aside a bit of the bacon, green onions and cheese to sprinkle on top for a nice appearance.