The bacon should be diced and cooked crisp. Reserve the fat.
The pumpkin should be cut in 1-inch pieces.
Heat the bacon fat and butter in a stock pot over medium-high heat. Add the pumpkin and saute for 15 minutes, stirring occasionally.
Pour in the stock and simmer covered until the pumpkin is very tender, about 30 minutes. Remove from heat.
Add the Marsala, thyme, and salt and pepper to taste. Process the soup in batches in a blender until smooth. Return to the stock pot.
Add the bacon. Simmer 10 minutes. Serve immediately, garnish with toasted pumpkin seeds.