Directions

1. Heat the oil in a multi-cooker or 4-quart or larger pressure cooker. Add the onion, carrot, celery and salt and sauté until just softened, about 2 minutes. (Do not let the onion brown.) Add broth and squash.
2. Lock the lid in place. If using the multi-cooker, select manual and set the timer for 5 minutes. (If using a pressure cooker, bring to high pressure over high heat. Reduce heat just enough to maintain high pressure and cook for 5 minutes. Turn off the heat.) Quick release the pressure or let it come down naturally. Remove the lid, tilting it away from you to allow steam to escape.
3. Squash should be very tender, if not, cover (without pressure) and heat over medium heat for a few minutes to soften. Transfer mixture to a blender. (Don't fill the blender container more than half-full, vent the cover, and hold a clean kitchen towel over the top while the blender is on.) Puree until smooth. (If mixture is too thick, add water.) Season with salt and pepper to taste and serve.