Just buy a bottle of marinara, maybe your favorite but preferably something whose first two ingredients begin with "whole crushed tomatoes, extra virgin olive oil" instead of "water, tomatoes, vegetable oil". You won't need the whole thing either, so you can save the rest for pasta the next night or something. Then just grab a couple mozzarella balls from the deli cheese bazaar, I avoid the shredded in the bag stuff, slice them as thin as you can get and go to town with the rest of your toppings.