Bake sweet potatoes at 400° about 1 hour 15 minutes.
Peel, mash lightly with potato masher and set aside.
Remove 6 slices of bacon and microwave until crisp, approximately 6 minutes between layers of paper towels.
Break bacon pieces up into small pieces and set aside for garnish.
Slice 2 or 3 green onions for garnish and set aside.
Meanwhile, Cut remaining bacon in 1 inch slices and sauté over medium heat in large stock pot.
After about 5 minutes add onions and continue sautéing until bacon is cooked.
Add flour and whisk to combine.
Slowly work in half-and-half until combined.
Turn heat to low.
Add cheese, parsley, chives, salt, pepper, and cayenne pepper to combine.
Now slowly stir in potatoes and milk.
Add more milk if the soup thickens too much.
Cover with lid and heat over low heat until the mixture is totally heated through, about 10-15 minutes.
Check for seasonings.
To serve: ladle soup into bowls.
Garnish with cheese, the tops of the green onions, and reserved bacon pieces.