Break spaghetti into thirds and cook according to package instructions, minus one minute. You want it to have a bit of a bite to it.
Preheat the oven to 350 F. In a large bowl, combine the cooked spaghetti and all the ingredients, except ½ cup of shredded cheddar cheese.
Spoon mixture into a 9 x 13-inch casserole dish and sprinkle the remaining ½ cup shredded cheddar on top. Bake for 30 minutes until the cheese is melted and bubbly.