Spaghetti Squash "Pizza" Bowls

Ingredients (11)

• 2 medium-to-large spaghetti squash (about 5.5 pounds total), or 3 small
• 4 teaspoons + 1 tablespoon extra-virgin olive oil, divided
• Salt
• Freshly ground black pepper
• 4 medium cloves garlic, pressed or minced
• 6 ounces (6 packed cups) baby spinach
• 2/3 cup (2 ounces) grated Parmesan cheese
• 2 cups marinara sauce (I used store-bought)
• 8 ounces (2 cups) grated part-skim mozzarella cheese
• Chopped fresh basil, for garnish
• Pinch of red pepper flakes, optional