How to Make It
Sprinkle the beef with the salt, pepper, paprika, and 2 tablespoons of the flour in a large bowl and toss to coat. Heat the oil in a large, deep skillet over medium-high. Add the beef and cook, stirring occasionally, until browned on all sides, about 8 minutes. Remove the beef from the skillet and set aside.
Add the onion to the skillet and cook, stirring often, until beginning to brown and tender, 4 to 5 minutes. Whisk together the stock and the remaining 2 tablespoons of flour. Add the stock mixture to the onion, stirring and scraping to loosen any browned bits from the bottom of the skillet. Bring to a simmer; reduce heat to medium and cook, stirring occasionally, until the sauce has thickened and reduced slightly, about 15 minutes. Meanwhile, cook the noodles according to the package directions.
Stir the beef and tomato into the sauce and cook until heated through, 3 to 5 minutes. Remove from heat and stir in the yogurt. Stir in the drained noodles and garnish with parsley.