The most problematic ingredient in any homemade or home-baked pizza is the crust. Either it comes out of the oven with the consistency of cardboard or it puffs up so much that it's practically a loaf of bread. You could continue to rummage through the freezer case at the grocery store looking for that one perfectly reliable brand. Or you could go to the Missouri Baking Company. The bakery sells two varieties of pizza dough, both equally worthy. The first is a precooked shell, if you like your pizza super-thin and crisp, St. Louis-style. (No, it does not come pre-sliced into squares.) The second is a more conventional dough that bakes up to the happy medium of crisp and chewy. Next problem: cheese, sauce and toppings. OK, you're on your own with those. But given that the Missouri Baking Company is located on the Hill, we don't think you'll have much trouble.