Timballo Spaghetti Casserole

Ingredients

• 1 tablespoon olive oil
• 1 (16 ounce) package spaghetti
• 2 (24 ounce) jars marinara sauce
• 3 cups cooked chicken breast meat, diced
• 1 large onion, diced
• 1 (7 ounce) package of sliced pepperoni, diced
• 1 green pepper, diced
• 1 (5 ounce) can mushroom pieces, drained
• 1 (3 ounce) can sliced black olives, drained
• 3 cups shredded mozzarella cheese
• 1 tablespoon grated Parmesan cheese, or to taste

Directions

Preheat oven to 350 degrees F (175 degrees C). Spread olive oil into the bottom of a cast-iron skillet or large baking dish.

Bring a large pot of lightly salted water to a boil. Cook spaghetti in the boiling water, stirring occasionally until cooked through but firm to the bite, about 12 minutes; drain.

Stir spaghetti, marinara sauce, diced chicken, onion, pepperoni, green pepper, mushroom pieces, and black olives together in a large bowl; transfer into the prepared cast-iron skillet. Top with mozzarella cheese in a layer and sprinkle with Parmesan cheese.

Bake in the preheated oven until casserole is bubbling, chicken is cooked through, and the cheese topping is lightly browned, about 30 minutes.