Preheat oven to 350 degrees. Mist a 9x13 baking pan with Pam. Cut squash in half lengthwise, scoop out seeds and place cut side down in baking pan. Bake 45 minutes until tender.
Remove squash from oven and let cool slightly. Remove squash from pan, and using a fork, scrape out flesh back into pan. Spread out slightly.
Mist a large skillet with Pam. Crumble sausage into skillet and cook over med-high heat until no longer pink, breaking into small pieces with spoon. Remove from heat.
Sprinkle 1 tbsp parmesan cheese and 1 tsp Mrs. Dash over squash. Top with tomato spinach and crumbled sausage; sprinkle with remaining 1 tbsp parmesan and remaining 1 teaspoons seasoning. Lightly coat the mixture's surface with Pam.
Bake 20-25 minutes more, or until casserole heats through and cheese melts.