Step 1

For the soup: Set a 6- or 8-quart Instant Pot® to medium saute setting (see Cook's Note) and line a plate with a paper towel. Add the pancetta to the pot and cook, stirring occasionally, until crisp and the fat is rendered, about 8 minutes. Remove the pancetta with a slotted spoon to the lined plate. Drain all but 2 tablespoons of the drippings from the pot and reserve.

Step 2

Add the carrots, celery, onion, sage, cumin, 2 teaspoons salt and 1/4 teaspoon pepper to the pot and cook, stirring occasionally, until the vegetables have softened, about 5 minutes. Add the squash and chicken stock. Follow the manufacturer's guide for locking the lid and preparing to cook. Set to pressure cook on high for 25 minutes. After the pressure cook cycle is complete, follow the manufacturer's guide for quick release and wait until the quick release cycle is complete. Be careful of any remaining steam and unlock and remove the lid. Use an immersion blender to puree the soup until smooth. Use the cream or water to thin the soup to the desired consistency. Season with additional salt and pepper.

Step 3

For the toppings: Meanwhile, heat 1 tablespoon of the reserved pancetta fat in a medium skillet over medium-high heat. Add the mushrooms, cumin and a generous pinch of salt. Cook, stirring occasionally, until the mushrooms have released all their liquid and turned brown and slightly crisp, 10 to 20 minutes. Remove the mushrooms and set aside for the topping.

Step 4

Ladle the soup into bowls and serve topped with the crisp pancetta, mushrooms, creme fraiche and chives.