Home made Mac and cheese

Ok I haven't put up a recipe in awhile but I just tried to make home made mac and cheese, for the first time in 4 years, and it actually turned out GOOD this time! :) I winged it, so here's my recipe:
1 box of elbow macaroni(my box was 13.25oz)
8oz sour cream
8oz cheddar cheese(shredded)
4oz mozzarella cheese(shredded)
1TBS soy sauce
1TBS mustard
1/2TBS garlic powder

Preheat oven to 350. Cook the macaroni according to the box directions. Drain. Put the macaroni back in the pot you cooked it in, and add everything except the mozzarella cheese. Stir well. Put in a 13X9" pan and sprinkle the mozzarella cheese on top. Bake for 10 minutes or until the cheese is melted on top.