1. In a large stock pot, put about 2-3 inches of water. Cover and bring to a boil. Wash outside of squash, cut squash in half and place in the stock pot of boiling water, flesh side down. Cover and boil for 15-20 minutes, until squash is tender.

2. Drain squash. Holding halves with a potholder, use a fork to scoop out the stringy "spaghetti". Set aside.

3. In a large stock pot or saute pan, melt butter. Add onions, garlic, and bell peppers and saute until tender. Add squash and cook and stir until heated through.

4. In a separate saucepan on low heat, melt the cream cheese. Add the sour cream, salt, pepper, and parsley flakes, stirring to make a smooth white sauce.

5. Stir the white sauce into the cooked squash mixture.

6. Grease a 9x13-inch baking dish. Spread the white squash mixture evenly over the bottom of the pan. Spread about 1 1/2 cups of the shredded mozzarella cheese over the squash.

7. In a large mixing bowl, combine the ground beef, spaghetti sauce, sugar, and Italian seasoning. Spread over the layer of shredded cheese. Top with the remaining shredded mozzarella cheese and cheddar cheese (if using). Sprinkle with dried basil or oregano flakes for garnish if desired.

8. Bake uncovered at 350 degrees (325 for glass dish) for 30-40 minutes, until casserole is hot and bubbly. Remove from oven and allow to cool slightly (10-15 minutes) before serving.