The accussative (the thing you make) in the first sentence wold be the noodles. The dative is an additional information "to whom" or "for whom" you make them. In the second sentence, you are the direct object that gets made ready, so you are in accussative.
That said, there are sometimes verbs that just demand a certain case for an object, regardless of the direct/ indirect classification.
That is actually a great question. Not because anyone needs to say that they are turning themselves into pasta, but rather because it illustrates how to construct such a sentence for when one might want to say something like, "Ich mache eine Geldbeutel aus einem Ohr der Sau."