Preheat oven to 400 degrees.
Cut spaghetti squash in half lengthwise. Place spaghetti squash cut side down on an oiled baking sheet and bake for 25-30 minutes or until the skin of the squash gives when you press on it. Then reduce oven heat to 350 degrees and bake for another 20 minutes.
Once squash is done cooking, remove threads using a fork and arrange them evenly in a 9 x 13 inch oiled baking dish.
Measure and stir the seasonings together.
Place a large pan over medium heat. Add beef and the seasonings.
Cook, breaking up the beef, until pink no longer remains. Remove beef to a bowl and drain fat if desired, (see note).
Add a drizzle of olive oil and saute onion for about 5 minutes until it’s starting to soften.
Stir in zucchini and cook for 2-3 minutes, then add the garlic and saute for another minute more.
Add pizza sauce, and salt and pepper and stir to combine. Return the beef to the pot and stir until mixed.
Pour the sausage mixture into the baking dish and mix well with spaghetti squash threads.
Drizzle the whisked eggs evenly over the casserole and mix together with a fork until you can no longer see the eggs.
Place in the oven and bake for 1 hour or until the top of the mixture forms a slight crust that doesn’t give when you press on it in the middle.
Let rest for 5 minutes before serving.