1. **Prep Steaks:** Remove the steaks from the refrigerator 30 minutes before cooking to let them reach room temperature (this ensures even cooking). Pat them thoroughly dry with paper towels. Season generously on both sides with salt and pepper.

2. **Sear:** Heat the olive oil in a large cast-iron skillet over medium-high heat until almost smoking. Add the steaks.

3. Sear for 3–4 minutes on the first side without moving them, until a deep brown crust forms.

4. Flip the steaks and add 2 tablespoons of butter to the pan. Cook for another 3–4 minutes (for medium-rare), basting the steaks with the melting butter continuously.

5. **Rest:** Remove the steaks from the pan and set them on a warm plate or cutting board. Tent loosely with foil to rest while you make the sauce.

6. **Make the Sauce:** Reduce the heat to medium. In the same pan (do not wipe it out!), melt the remaining 2 tablespoons of butter.

7. Add the minced shallot and cook for 1–2 minutes until soft. Add the garlic and cook for 30 seconds until fragrant.

8. **Deglaze:** Pour in the beef broth (or wine) and scrape the bottom of the pan with a wooden spoon to release the brown bits (fond). Let it simmer for 2 minutes to reduce slightly.

9. **Simmer:** Stir in the heavy cream, Dijon mustard, and thyme. Bring to a gentle simmer and cook for 3–5 minutes until the sauce thickens enough to coat the back of a spoon.

10. **Finish:** Stir in the Parmesan cheese until melted and smooth. Taste and adjust salt and pepper if needed.

11. **Serve:** Pour the hot cream sauce generously over the rested steaks and serve immediately.