This is a decadent dish with lots of flavor.
Undercooking the pasta before it enters the oven remains the most frequent error committed when preparing baked macaroni dishes. Because the noodles continue absorbing moisture and residual heat throughout a twenty-to-thirty-minute bake at 375 degrees Fahrenheit, starting with pasta that is already fully softened guarantees a mushy final texture. Pulling penne or elbow pasta from boiling salted water at the twelve-minute mark leaves a firm center that withstands the heavy dairy bath.
Allow the assembled casserole to rest for ten minutes after exiting the oven so the internal starches can stabilize and thicken the sauce. Proper temperature management during the baking phase prevents the delicate shellfish proteins from turning tough and rubbery.