Tofu Rigatoni Casserole

Ingredients

• 1/4 cup extra-virgin olive oil, plus more for drizzling
• 1/2 onion, finely chopped
• 3 garlic cloves, finely chopped
• 1 (28-ounce) can crushed tomatoes
• 1 pinch dried oregano
• 1 (12- to 14-ounce) package firm tofu, drained
• 1 large egg
• 1 pinch grated nutmeg
• salt and freshly ground black pepper to taste
• 1 (10-ounce) package frozen spinach, defrosted and drained
• 1 (1-pound) box rigatoni, cooked al dente and drained
• 1 pound fresh mozzarella, grated (about 4 cups)
• 3 ounces grated parmesan (about 3/4 cup)