01 - Bring a large pot of salted water to a rolling boil. Cook rigatoni until al dente, then drain thoroughly.
02 - Heat a skillet over medium-high heat. Add ground beef and chopped onion, stirring frequently until beef is fully browned and onion is tender. Drain excess fat.
03 - Stir in prepared horseradish, beef broth, and crème fraîche with the beef and onion mixture. Reduce heat and simmer until sauce is smooth and gently thickened.
04 - Fold cooked rigatoni into the sauce, mixing until evenly coated. Serve immediately, garnished to preference.