Let the pasta bake rest for about 5–10 minutes before serving. This short rest helps the sauce thicken slightly and makes it easier to scoop into neat servings.
To lean into that classic pot pie flavor, stir in a pinch of dried thyme, poultry seasoning, or rubbed sage along with the soup. If you miss the flaky crust, crush a few buttery crackers or plain potato chips and scatter them over the top during the last 10 minutes of baking for a bit of crunch. For a creamier casserole, add 1/2 cup of milk or half-and-half to the mixture before baking. You can swap the frozen mixed vegetables for just peas and carrots or whatever you have on hand—leftover roasted vegetables work nicely, too. If you’re cooking for a smaller household, divide the mixture between two smaller baking dishes; bake one and freeze the other (tightly wrapped) before baking for a future meal. For extra protein, use whole-wheat pasta or add a handful of shredded cheese directly into the mixture. And if you prefer a lighter version, use a reduced-fat creamy soup and add more vegetables, letting the pasta share the stage instead of taking the lead.