It's better that you don't, as 12 ounces is the perfect amount of pasta for this recipe. I don't bother measuring the pasta exactly, just eyeball 3/4 of a box. I don't recommend using a full box of spaghetti (16 ounces) for this recipe. There will be too much pasta and not enough sauce, making the flavor a little bit bland. You can try making this recipe using 8 ounces of pasta - I've haven't tried yet because it's not enough to feed my family. I'm guessing it will work fine, but if you try it let me know!