{^ BAKED PASTA^ }

Here’s something I’ve always wondered: when baking
pasta, as in, say, lasagna or baked ziti, why do you always
cook the pasta first? Aren’t you inviting trouble by cooking
it once, then proceeding to put it in a casserole and cooking
it again? Well, there’s the obvious first part of the answer to
this question: pasta needs to absorb water as it cooks—a lot
of water, around 80 percent of its own weight when
perfectly al dente. So, add raw pasta directly to a baked
pasta dish, and it will soften all right—it’ll also suck up all
of the moisture from the sauce, leaving it dry or broken.
Here’s the thing: Dried pasta is made up of flour, water,
and, on rare occasion, eggs. Essentially it’s composed of
starch and protein, and not much else. Starch molecules
come aggregated into large granules that resemble little
water balloons (see “How Starch Thickens,” here). As they
get heated in a moist environment, they continue to absorb
more and more water, swelling up and becoming soft.
Meanwhile, the proteins in the pasta begin to denature,
adding structure to the noodles (something that is much
more obvious when cooking soft fresh egg-based pastas).
When the stars are aligned, you’ll manage to pull the pasta
from the water just when the proteins have lent enough
structure to keep the noodles strong and pliant and the
starches have barely softened to the perfect stage—soft but
with a bite—known as al dente.