To roast pumpkin, preheat oven to 400 degrees F. Cut whole pumpkin in half and then cut each half into several pieces. Discard seeds or reserve for another use. Place pumpkin on a baking sheet, drizzle with olive oil, and season with salt and pepper. Roast in oven until tender but not falling apart, about 30 to 40 minutes. Let cool, peel away skin, and dice.