Stir 1 cup marinara sauce into spaghetti. Divide evenly into 5 servings. Butter one side of each slice of bread. You can also use mayonnaise spread on the bread if you prefer.

Place one slice of bread onto the center section of your bottom waffle iron (buttered-side down). Add one slice of cheese on top of the bread. Carefully twirl spaghetti with a large fork and then place on top of the cheese. Add a few small spoonfuls of marinara sauce over spaghetti. Add another slice of cheese on top. Top with another slice of bread (buttered-side up). Close waffle iron. The waffle iron will not close all the way but you can press on it gently and it should sink down further as the sandwich cooks.

Set your waffle iron to medium-high heat and cook until cheese is melted and bread is dark golden brown. Repeat steps 2-3 to make remaining sandwiches.