Preheat oven to 375°F (190°C). Lightly grease a 9x13 casserole dish.
In a bowl (or directly in the baking dish), whisk together milk, pumpkin puree, blended cottage cheese, broth, flour, Dijon, garlic powder, onion powder, nutmeg, and a good pinch of salt and pepper until smooth.
Stir in uncooked pasta, 1 ½ cups cheddar, mozzarella, and Parmesan. Make sure pasta is submerged.
Cover tightly with foil and bake for 30 minutes.
Remove foil, stir well, and add a splash of liquid if needed. Sprinkle with remaining cheddar. If using breadcrumbs, toss them with olive oil or melted butter and scatter over top.
Bake uncovered for 15 minutes until pasta is tender and topping is golden and bubbly.
Let rest 5 minutes before serving, then portion into Bentgo containers for meal prep.