Preheat oven to 350 degrees F (177 degrees C). Cut the tops off peppers, and clean out the seeds and membranes. If peppers won’t stand up, cut a little piece off the bottom to level them. Place peppers on a baking sheet, and drizzle with oil. Bake for 25 minutes, or until they start to soften. Remove from the oven and allow to cool.
Pour the oil from the peppers into a frying pan, and add the onions, mushrooms, zucchini, and oregano. Season the vegetables with the salt and pepper to taste, and sauté over high heat until they start to soften. Add the tomatoes, rice, water, and bouillon cube, and simmer for about five minutes. Adjust the seasoning.
Fold in bacon, basil, and mozzarella, and divide among the peppers. Sprinkle Parmesan on top of peppers and bake in the middle of the oven for 15 minutes, or until cheese has melted and the filling is hot.
