A lot of food mashups end up verging strongly into This Is Why You're Fat territory. Then again, some are truly delicious. This is one of those.
Pizzagna is just what it sounds like: a few whole, thin-crusted, sauced-to-the-edge bar style pies layered into a casserole dish with extra sauce and cheese, then covered and baked. Why would one want to do this, you might ask?
Well, as the whole thing bakes, the extra sauce and cheese melt into the crust, softening it into an almost pasta-like consistency. In fact, the whole thing ends up with a texture remarkably like lasagna, except that it's got the awesome smoky char of a well-browned pizza crust. Of course, pizza-parlor toppings add even more pizza-ness to the casserole. For this one, I used five different pies with five different toppings: Italian sausage, hot soppressata, bacon, ham, and pepperoni. You can mix it up with whatever you'd like.
The only slightly tricky part is cutting the pies to fit the casserole. I usually fit slices in jigsaw-style, then cut out smallish pieces to fill in the gaps. If you happen to own a large round cake pan the size of a pizza, then you're in luck—just layer'em in!
I'm not kidding when I say that it takes a considerable amount of work to make one of these—making dough, making sauce, grating cheese, baking pies, cooling, layering, and baking, but the results are well worth it. All the comfort of lasagna, with the fun of a pizza.
And if you want to cheat by just ordering a few thin crust pies, I won't tell.