Bring a large pot of lightly salted water to a rolling boil, add elbow macaroni, and cook until just al dente (7–8 minutes). Drain and set aside.

Steam cauliflower florets, sliced carrots, and fresh spinach until tender (about 7 minutes), then blend with ½ cup milk until perfectly smooth and creamy.

In a medium saucepan over medium heat, melt butter, whisk in flour, and cook for 1 minute until bubbling and lightly golden to form a roux.

Gradually whisk in the remaining milk and veggie purée, cooking until the sauce thickens into a lush, velvety texture (3–4 minutes).

Remove from heat, then fold in sharp cheddar cheese until it fully melts into a silky, golden sauce.

Toss cooked macaroni with the cheese sauce, transfer to a greased baking dish, top with buttered breadcrumbs and parmesan, and bake at 350°F for 15 minutes.