Cook a pound of elbow macaroni in a large pot of salted boiling water until just al dente, about 8 minutes. Drain and set aside.
In a heavy-bottomed saucepan, melt 4 tablespoons of butter over medium heat until it starts to smell nutty and bubbles gently.
Whisk in the flour and cook for about 1 minute, stirring constantly until the mixture turns a light golden color and smells toasty.
Gradually pour in the milk, whisking steadily to prevent lumps. Bring the mixture to a gentle simmer, and cook for about 5 minutes until it thickens and becomes glossy.
Add the grated sharp cheddar cheese to the sauce, stirring until it melts completely into a smooth, cheesy sauce. Stir in hot sauce and plenty of freshly cracked black pepper for bold flavor.
Mix the cooked pasta into the cheese sauce, making sure all the noodles are well coated and gooey.
Transfer the cheesy pasta mixture into a greased baking dish, spreading it out evenly.
Toss the panko breadcrumbs with melted butter and paprika, then sprinkle evenly over the top of the pasta.
Place the dish under a preheated broiler set to high, and cook for 3-5 minutes until the breadcrumbs turn golden brown and crispy, and the cheese is bubbling around the edges. Keep a close eye to prevent burning.
Remove from the oven and let it rest for 5 minutes—this helps the cheese set slightly and makes serving easier. The top should be crispy and golden, with bubbling, cheesy goodness underneath.
