Cook the pasta: Boil in salted water until just shy of al dente (1–2 minutes less than package). Drain and set aside.
Make the sauce base: In a skillet over medium heat, melt butter.
Add onion and celery; cook 4–5 minutes until soft. Stir in garlic for 30 seconds.
Build the cream sauce: Sprinkle in flour and cook, stirring, for 1 minute. Gradually whisk in milk and broth.
Simmer 3–4 minutes until thickened.
Flavor and cheese: Stir in Dijon, cheddar, Parmesan, lemon zest, and lemon juice. Season with salt and pepper. The sauce should be creamy and well-seasoned.
Add tuna and peas: Fold in drained tuna and frozen peas.
Break up tuna lightly to keep some texture.
Combine with pasta: Toss sauce with cooked pasta until evenly coated. Taste and adjust seasoning.
Prep the pangrattato: In a small pan, warm olive oil over medium heat. Add breadcrumbs and garlic; toast 2–3 minutes until golden.
Off heat, stir in parsley, lemon zest, salt, and pepper.
Assemble: Lightly oil a small, air fryer–safe baking dish that fits your basket (about 6–7 inches wide or 1.5–2 quarts). Spoon in the pasta mixture and smooth the top.
Air fry: Heat the air fryer to 350°F (175°C). Cook the pasta bake for 8–12 minutes until hot and bubbling.
Top and finish: Sprinkle the pangrattato evenly over the top.
Air fry another 2–4 minutes until the crumbs are crisp and lightly browned.
Rest and serve: Let the bake sit for 5 minutes. The sauce will set slightly, making it easier to serve clean slices.