Cut top from pumpkin; scrape out seeds and fibers. Simmer in salted water to cover for 20 to 25 minutes or until almost tender. Drain. Brown beef and onion. Add peppers and garlic. Cook one minute. Remove from heat, stir in remaining ingredients. Spoon into pumpkin. Place "lid" on top. Brush pumpkin with oil.
Bake at 180ºC or 1 hour.
Let stand 10 minutes.
Cut into edges to serve.