Bring a large pot of salted water to a boil. Stir in the elbow macaroni. Boil until just tender (don’t overcook it).
Drain the pasta in a colander and spray cool water over it to keep it from sticking together.
In a large pot, melt butter over medium heat. Whisk in the flour, salt, and black pepper. Stir to form a thick paste.
Slowly whisk in the milk, ¼ cup at a time. Heat the milk mixture over medium heat for a few minutes, whisking frequently, until it thickens and begins to bubble around the edges. Do not let the sauce boil.
Whisk in grated cheddar cheese. Stir until cheese is melted and a thick sauce forms. Stir in the Greek yogurt until smooth. Stir the cooked macaroni into the sauce, making sure all the pasta is evenly coated by sauce.
Pour macaroni with cheese sauce into a deep baking dish. Make sure to spread it out into an even layer and scrape all remaining sauce from the pot over the top of the pasta.
Mix together the breadcrumbs and smoked paprika and evenly sprinkle over the top of the pasta. Place in the oven and bake at 220 degrees °C for 15 minutes until the top and breadcrumbs are golden brown to your liking.