Squash, Sausage, and Spinach Pizza

Name: Squash, Sausage, and Spinach Pizza
Cuisine: European, Mediterranean, Italian
Ingredients: Pizza dough (homemade or store bought); White sauce (homemade or store bought); 2 tbsp olive oil; Salt and pepper; Half a small butternut squash, thin sliced; ½ cup browned sausage or turkey bacon; 2 handfuls of Fifth Season spinach; 1/4 sliced onion; 1/2 tsp dried oregano; 2 cups mozzarella cheese, shredded; Parmesan cheese to finish