Slice the beef thinly against the grain. This ensures tenderness. Pat the pieces dry with paper towels—dry beef sears better.

Heat 1 tablespoon olive oil and 1 tablespoon butter in your skillet over medium-high heat. Add the beef in batches to avoid overcrowding. Cook for 1–2 minutes per side until browned but not fully cooked. Remove and set aside.

In the same pan, add the remaining butter. Add the onion and cook for 2–3 minutes until softened. Add the garlic and cook for 30 seconds until fragrant. Add mushrooms and cook until they release moisture and turn golden.

Pour in the beef broth, scraping up browned bits from the bottom (this adds essential flavor). Add Worcestershire sauce, Dijon mustard, smoked paprika, salt, and pepper. Stir and bring to a gentle simmer.

Reduce heat to medium-low and stir in the heavy cream. Let it simmer gently until slightly thickened.

If you prefer a thicker sauce, whisk ½ teaspoon xanthan gum with a small amount of sauce liquid until dissolved, then mix back into the pan.

Add the seared beef back into the sauce. Let it simmer for 5–7 minutes until heated through and fully cooked. Taste and adjust seasoning.

Sprinkle with fresh parsley and serve warm.