Pumpkin surprise

This is a fun fall dinner that I make annually in October. The novelty almost persuades my picky eaters to have more than one bite, and the rest of us enjoy it. I originally got the recipe from a college roommate, but I've since tweaked it a bit and lost the original. I found another version here and used it as a base with what I remember of my own recipe.

Dinner-in-a-pumpkin recipe:

medium sized pumpkin (4 lbs), gutted and seeded (save the lid!)
1 1/2 lbs. lean ground beef
1 clove garlic, crushed
1 medium onion, chopped
1 green pepper, chopped
2-3 celery stalks, chopped
1-2 zucchini
1 (4-oz.) can mushrooms or sliced fresh mushrooms
1/4 cup low sodium soy sauce
2 Tbsp. brown sugar
2 cups cooked rice
1 cup chicken or beef broth
2 Tbsp cornstarch, mixed into 1/4 c. milk
dash of worcestershire sauce (optional, to taste)
salt and pepper, to taste

Preheat oven to 350 degrees. In a large skillet, brown meat with garlic, green pepper, onion, and celery. Add the zucchini and mushrooms; cook for a 2-3 minutes. Next, add the soy sauce, sugar, broth, and rice. Mix well. Add the milk/cornstarch mixture and cook until sauce thickens. Season to taste; then scoop into pumpkin cavity. Add the lid (unless the stem makes it too tall for your oven), then bake for 90 minutes. You can cook it directly in the oven, but I'd advise setting it in a 9x13 pan, just in case your pumpkin softens, half collapses, and spills on the bottom of your oven. (Strictly a hypothetical scenario, of course. Ahem.)

Before serving, if you want to make it a little more festive, use toothpicks and olives to make a face on the pumpkin. (I have never done this because I hate olives, but it could be cute.) To serve, scoop out part of the baked pumpkin, along with the filling, onto each plate.