01 - Rinse rice under cold water until clear. In a saucepan, bring 2 cups water and 1/2 tsp salt to a boil. Add rice, reduce heat to low, cover, and simmer for 15–18 minutes until water is absorbed. Remove from heat, let stand covered for 5 minutes, then fluff with a fork.
02 - Pat beef dry, then toss with 1 tbsp flour, salt, and pepper.
03 - Heat 1 tbsp olive oil in a large skillet over medium-high heat. Add half the beef and sear 1–2 minutes per side until browned. Remove and repeat with remaining beef, adding more oil if needed.
04 - Reduce heat to medium. Melt butter in skillet, sauté onions 2–3 minutes until soft. Add mushrooms and cook 5–6 minutes until tender and golden.
05 - Stir in garlic and paprika; cook 30 seconds until fragrant.
06 - Pour in beef stock, Dijon mustard, and Worcestershire sauce. Scrape browned bits from the pan. Simmer 3–4 minutes to reduce slightly.
07 - Lower heat, stir in sour cream until smooth. Return beef and juices to skillet. Warm gently for 2–3 minutes without boiling.
08 - Adjust seasoning with salt and pepper to taste. Serve stroganoff over rice and garnish with fresh parsley.