Preheat the oven: Heat to 375°F (190°C). Lightly grease a 9x13-inch baking dish.

Cook the pasta: Bring a large pot of salted water to a boil. Cook pasta until just shy of al dente, 1–2 minutes less than the package suggests. Drain and set aside.

Sauté aromatics: In a skillet, warm olive oil over medium heat. Add onion and a pinch of salt. Cook 4–5 minutes until soft. Stir in garlic and cook 30 seconds until fragrant.

Prep the sauce: In a large bowl, whisk Greek yogurt, cottage cheese, and milk until smooth. Stir in Dijon, lemon zest, lemon juice, oregano, thyme, black pepper, and a light pinch of salt.

Add cheese: Fold in 1 cup shredded cheese and the Parmesan. Reserve the remaining 1/2 cup cheese for topping.

Combine tuna and veg: Flake the drained tuna into the bowl. Add the onion-garlic mixture and your vegetables (if using broccoli, steam or blanch briefly so it’s just tender). Mix gently to keep tuna chunky.

Bring it together: Add the cooked pasta to the bowl and toss until evenly coated. Taste and adjust salt, pepper, or lemon juice. The mix should be creamy but not soupy.

Assemble: Spread the mixture into the baking dish. Top with the remaining 1/2 cup shredded cheese. If using, sprinkle breadcrumbs over the top and mist with a little olive oil for extra crunch.

Bake: Place in the oven for 18–22 minutes, until bubbling at the edges and the top is lightly golden.

Rest and serve: Let it rest 5 minutes. Garnish with chopped parsley or a pinch of red pepper flakes if you like. Serve warm.