- 2 spaghetti squash, halved lengthwise and seeded
- 1 tablespoon olive oil
- salt and ground black pepper to taste
- 2 (16 ounce) packages shredded mozzarella cheese, divided
- 1 (15 ounce) container ricotta cheese
- 1 egg
- 1/2 cup Parmesan cheese
- 1 (24 ounce) jar spaghetti sauce
- Preheat oven to 375 degrees F (190 degrees C).
- Brush the inside of the squash halves with olive oil; season with salt and pepper. Place cut-sides up on a baking sheet.
- Bake in the preheated oven until softened, about 45 minutes. Remove from oven. Cool until easily handled, 5 to 10 minutes. Scrape out strands of squash with a fork and transfer to a bowl.
- Preheat oven to 350 degrees F (175 degrees C).
- Mix half of the mozzarella cheese, ricotta cheese, egg, and Parmesan cheese together in a bowl. Stir into the squash. Stir in 2 or 3 tablespoons spaghetti sauce to turn mixture pink.
- Spread half of the squash mixture in a 9×13-inch baking dish. Ladle half of the spaghetti sauce on top. Sprinkle with half of the remaining mozzarella cheese. Layer remaining squash mixture, spaghetti sauce, and mozzarella cheese on top.
- Bake in the preheated oven until mozzarella cheese is melted and browned, 30 to 45 minutes.