Preheat oven to 400°F.
Place cleaned potatoes in a baking dish. Place in preheated oven and bake until tender, but not mushy.
Remove potatoes from oven. Set aside to cool enough to handle.
Remove peels. Cut potatoes into 1/2-inch cubes. Place in a bowl and set aside.
Place butter in large saucepan. Place pan over low heat.
When butter has melted and is hot (do not burn), add onions. Sauté over low heat for 10 minutes or until onions are transparent. Do not burn.
Add flour to onions and butter. Cook, stirring constantly, 4 to 5 minutes until flour is absorbed.
In a medium bowl, add water, chicken base, potato flakes, basil and hot pepper sauce. Stir until thoroughly mixed and no lumps remain. Add to onion mixture, stirring constantly to prevent lumps from forming.
Increase heat to medium. Continue cooking until soup begins to simmer.
Add cream and milk, stirring until smooth and lightly thickened.
Simmer 15 minutes. Do not boil. Soup should just simmer lightly.
Add prepared cubed baked potatoes. Stir gently to combine. Heat just until the potatoes are warmed.
Taste. Add salt and pepper, to taste.
Remove from heat and serve at once.
Top with cheese, sliced green onions and bacon or serve separately and allow guests to top soup as desired.