spaghetti casserole recipe

Ingredients: 12 ounces spaghetti 1 pound ground beef or Italian sausage 1 small onion, finely chopped 2 cloves garlic, minced 1 jar (24 ounces) marinara sauce 1 can (14.5 ounces) diced tomatoes, drained 1 teaspoon dried oregano 1 teaspoon dried basil 1/2 teaspoon salt 1/2 teaspoon black pepper