Bring a large pot of salted water to a boil. Add the cauliflower florets and cook for about 5 minutes until tender but still firm. Using a slotted spoon, remove the cauliflower and transfer it to a bowl. In the same water, add the macaroni and cook according to package instructions until al dente. Drain and set aside.
Reduce the heat to low and add in the shredded cheddar cheese, Dijon mustard, smoked paprika, onion powder, salt, and pepper. Stir continuously until the cheese melts and the sauce is creamy. If the sauce is too thick, add a splash more milk.
In a large mixing bowl, combine the cooked elbow macaroni and cauliflower florets. Pour the cheese sauce over the top and gently mix until well coated.
Preheat your oven to 350. Transfer the macaroni and cheese mixture into a greased 9x13-inch baking dish. In a small bowl, mix the panko breadcrumbs with a drizzle of olive oil and a pinch of salt, then sprinkle evenly over the top of the mac and cheese.
Bake in the preheated oven for 25-30 minutes, or until the top is golden brown and bubbling.
Let it cool for a few minutes before garnishing with fresh parsley. Serve hot, and enjoy your Cheesy Cauli-Mac Delight!