Slice beef into strips. Slice mushrooms, thinly slice onion and mince garlic.
Heat up olive oil in a large non-stick skillet over high heat. Sear beef until golden brown, then remove from heat.
Add sliced onion to the skillet and cook over medium heat for 5 minutes or until softened.
Increase the heat to high, and add mushrooms. Cook for 2-3 minutes until browned.
Stir in garlic and paprika and cook for 1 minute.
Add worcestershire sauce and beef stock and bring to a boil, then reduce heat to low.
Return beef to the skillet and let simmer for 1-2 minutes. Stir in the sour cream and remove from heat.
Taste and season with pepper and salt if necessary. Serve immediately with noodles of choice. Enjoy!