Prep and season steaks.
Remove steaks from the fridge to come to room temperature. Pat dry. Season both sides with half the salt and pepper (1 tsp each).

Sear steaks.
Heat 1 tbsp olive oil and 1 tbsp butter in a skillet over medium‑high heat. Sear steaks for 3–4 minutes per side for medium‑rare. Transfer steaks to a plate and tent with foil to rest.

Sauté aromatics.
In the same pan, add the remaining olive oil and butter. Sauté the shallot for about 2 minutes until softened.

Cook mushrooms and garlic.
Add sliced mushrooms and cook until lightly golden. Stir in garlic and tomato paste; cook for about 30 seconds until fragrant.

Deglaze with Cognac.
Carefully pour in the Cognac or brandy. If desired, flambé briefly (step optional) or allow to reduce for 1–2 minutes to evaporate alcohol.

Add flavorings.
Stir in Dijon mustard, Worcestershire sauce, and beef broth. Let simmer and reduce slightly, about 2 minutes.

Finish with cream and herbs.
Pour in the heavy cream. Stir and let the mixture gently simmer until sauce slightly thickens (around 2–3 minutes). Stir in half the chopped parsley. Adjust seasoning with remaining salt and pepper as needed.

Serve.
Return steaks to the pan just to rewarm briefly, spoon sauce over them, and serve immediately garnished with remaining parsley.