Sabar and Mom have it pretty well figured out. You might also try shell pasta. It will cook nicely if your water is hot enough to start and your cozy is insulated well. Use from 1/2 to 2/3 the regular amount of water and pour off the extra water to make the sauce when the pasta is right. I mix in some olive oil when adding the water and after pouring off the excess. It keeps the pasta from forming a sticky mass.

And always experiment at home before taking a recipe on the trail.