Step 1

Melt the butter in a large pot or dutch oven over low to medium heat. Add the onion, apple, squash, and potato. Season with salt and pepper, cook for 7 to 10 minutes. You don't want anything to brown just cook and soften.

Step 2

Stir in the poultry seasoning and flour. Raise the heat to medium high and add the cider, slowly add the stock stirring as you go. Cook until thickened. Add the milk and bring to a boil. Reduce to a simmer and cook for about 10 minutes.

Step 3

If you are using the prosciutto add it to a small fry pan with a touch of oil or butter to crisp up over medium heat. Drain on a paper towel and reserve.

Step 4

Reduce to low and stir in the cheese until it is all melted. At this point you can either put the soup in a blender in batches or use an immersion blender right in the pot. Puree until smooth. Season one last time with salt and pepper, ladle in bowls and top with any extra cheese, chives, and prosciutto. Serve with crusty bread.