Heat oven to 400F. Using a large metal spoon, scoop out the seeds and insides of the pumpkin. Save the seeds for roasting. Use a sharp chef's knife to cut slices of pumpkin, 1-inch thick.
Place pumpkin slices on baking sheet. Drizzle with olive oil and rub on both sides of pumpkin. Season with salt, spices and brown sugar. Roast for 18-20 minutes, depending on thickness of pumpkin slices (check at 15 minute mark).