This a brag post, not a blog post. I knocked it out of the park on my second attempt. I finally solved the brittle mozzarella mystery (turns out the curds-cum-cheese need to be too hot to handle for best fusing results), and the end result was a shreddable softball*. Instead of slices of garlic and chunks of onions, Mrs. Gastro blended the two into a pastelike substance that imparted flavor to the sauce without being a nuisance to the texture. And the "cup of water in the broiler" trick gave the crust an audible crunch that it lacked in the first attempt. Top the whole thing off with some sweet italian sausage (procured from the Chestnut Hill Farmers' Market), and you're saying "holy shit" all over again. Buen provecho.
*While making fresh mozzarella cheese is wonderful fun, the price of a gallon of milk and the resulting yield is about the same as you would pay for a real Italian grandmother to make it (mozzarella di lehigh valley dairy, not mozzarella di bufala).