Heat a large skillet over medium-high heat and drizzle in a tablespoon of olive oil. Sear the beef sirloin until nicely browned on each side, about 5-8 minutes total. Remove and set aside.

In the same skillet, add chopped onion and sauté for about 3 minutes until translucent. Add minced garlic and cook for an additional minute, then add sliced mushrooms. Sauté for about 5 minutes until golden and tender.

Return the beef to the skillet, add beef broth and Dijon mustard, stirring to combine. Bring to a gentle simmer and cook for about 5 minutes.

Lower the heat and stir in sour cream until smooth. Warm gently for another 2 minutes, tasting and adjusting seasoning.

Cook your choice of egg noodles, mashed potatoes, or rice according to package instructions.

Plate your base and pour the Beef Stroganoff over the top, garnishing with chopped parsley.