My sister-in-law served this at her anniversary party and everyone left with the recipe

Taste the sauce and season with kosher salt and black pepper if needed, keeping in mind that Parmesan and jarred Alfredo can already be fairly salty. Whisk again to distribute the seasoning.

Pour the sauce mixture evenly over the pasta and chicken in the baking dish. Use a wooden spoon to gently stir and nudge the pasta so everything is coated and there are no big dry pockets. Smooth the top into an even layer.

Cover the baking dish tightly with foil, making sure it is well sealed around the edges to trap steam. Place the dish on the middle rack of the preheated oven and bake for 35 minutes. The steam inside will help the pasta cook through and keep the chicken moist.

After 35 minutes, carefully remove the foil (watch for hot steam). Stir the pasta well, scraping up any sauce from the corners and redistributing the chicken throughout. The pasta should be mostly tender at this point, with a little bite in the center.

Sprinkle the remaining 1/2 cup grated Parmesan evenly over the top of the pasta. Return the uncovered dish to the oven and bake for another 10–15 minutes, until the top is lightly golden in spots, the sauce is bubbling around the edges, and the chicken pieces are cooked through (165°F/74°C in the thickest pieces).

If you’d like a deeper golden top, you can broil the dish on high for 1–2 minutes at the end. Watch it closely so the cheese doesn’t burn—those few seconds under the broiler make the top extra tempting in photos and at the table.

Remove the baking dish from the oven and let it rest for 5–10 minutes. The sauce will thicken slightly as it cools, which helps it cling to the pasta. Give everything a gentle stir with a wooden spoon, scooping from the bottom so each serving gets plenty of creamy sauce, chicken, and sun-dried tomatoes.

Serve the pasta straight from the baking dish, using a wooden spoon to lift generous scoops into bowls or onto plates. Garnish with an extra sprinkle of Parmesan if you like. Expect people to ask for the recipe—have your phone ready, because they’ll probably just snap a quick picture of the dish and your notes, imperfections and all.

For a bit of heat, add 1/4–1/2 teaspoon red pepper flakes to the Alfredo sauce mixture before baking; that touch of spice plays well with the sweetness of the sun-dried tomatoes.

If you prefer dark meat, boneless skinless chicken thighs work beautifully and stay very tender—just trim excess fat and cut into small pieces so they cook in the same time frame. You can also substitute a different short pasta, such as cavatappi or shells, but avoid very large shapes, which can stay too firm in the center.

For a slightly lighter version, use a lighter Alfredo sauce or replace 1/2 cup of the Alfredo with low-sodium chicken broth, reducing the added water by 1/2 cup to keep the sauce from becoming too thin. Stir in a couple of handfuls of baby spinach after the initial covered bake, right before adding the final Parmesan, if you’d like some greens folded in.

Food safety tips: Always use separate cutting boards and knives for raw chicken and ready-to-eat ingredients, and wash your hands, board, and knife thoroughly with hot, soapy water after handling raw poultry. Make sure the chicken reaches an internal temperature of 165°F (74°C) in the thickest pieces before serving; if it’s not there after the suggested baking time, cover loosely with foil and bake a few minutes longer. Cool leftovers promptly and refrigerate within 2 hours; reheat thoroughly until steaming hot before eating.