Cut the squash into large pieces. Using a sharp knife, carefully remove the skin, wasting very little. Scoop out and discard the seeds. Chop the squash into small chunks. Remove all fat from the bacon and roughly chop it into small pieces.
Heat oil in large saucepan. Add the onions and garlic and cook for 3 minutes, or until they begin to become soft. Add the bacon and cook for about 3 minutes. Stir in the spices and cook over low heat for a minute longer.
Add the chopped squash, potatoes, and stock. Bring to a boil and simmer for 15 minutes, and or until the squash and potatoes are tender.
Blend the cornstarch with 2 tablespoons water and add to soup with the sour cream. Bring to a boil and simmer, uncovered, for 3 minutes. Adjust the seasoning and add hot pepper sauce to taste. Ladle the soup into warm bowls and sprinkle cheese on top. Serve immediately with crusty bread to scoop up the melted cheese.