Peel and split pumpkin in half. Remove and discard seeds. Julienne pumpkin meat. Cut remaining meat into 1-inch cubes. Heat the oil and water in a 5-quart saucepan over medium heat. When hot add the chopped celery, leeks, and onion. Season with salt and pepper and sauté for 5 minutes. Add pumpkin cubes and continue to sauté for an additional 5 minutes. Add chicken stock, bring to a simmer, and then adjust heat to maintain stock at a low simmer for 20 to 25 minutes. Melt butter in 2 1/2 quart saucepan over low heat. Add flour to make a roux. Whisk vigorously until smooth. Add this mixture to a 5-quart saucepan with remaining stock and vegetables. Whisk until smooth. Allow to simmer for 10 minutes. Adjust seasoning with salt and pepper. Remove soup from heat. Puree in good processor and then strain. Return soup to heat and bring to a simmer. Heat cream and pumpkin julienne together in a nonstick pan. When warm, add to soup. Adjust seasoning with salt and pepper. Portion soup into warm serving dishes and garnish with peanuts.