Set a large pot of salted water to boil and cook the pasta until just al dente, about 1 minute less than package instructions. Drain and set aside.
In a saucepan, melt 2 tablespoons of butter over medium heat until it starts to foam and smell nutty.
Whisk in the flour and cook for 1-2 minutes, stirring constantly, until the mixture bubbles and turns a light golden color.
Gradually pour in the heavy cream, whisking constantly to prevent lumps, and bring to a gentle simmer until the sauce thickens, about 3-4 minutes.
Add the shredded cheddar cheese in small handfuls, stirring after each addition until fully melted and smooth. Stir in smoked paprika and Dijon mustard, then season with salt and pepper to taste.
Combine the cooked pasta with the cheese sauce, stirring well to coat every piece evenly.
Preheat your oven to 200°C (400°F). Transfer the cheesy pasta mixture into a greased baking dish, spreading it out evenly.
In a small bowl, toss the panko breadcrumbs with the remaining 2 tablespoons of melted butter, paprika, and a pinch of salt. Spread the toasted crumbs evenly over the pasta.
Bake in the preheated oven for 15-20 minutes, until bubbling around the edges and the breadcrumb topping is golden brown and crispy.
Remove from the oven and let sit for 5 minutes to allow the sauce to set. Serve hot, with a crispy topping and a gooey, cheesy center.
