Remove the steaks from the refrigerator 30 minutes prior to cooking; season generously with salt and pepper.

Heat olive oil and butter in a cast-iron skillet over high heat. Sear the steaks for 3–4 minutes per side (adjust to desired doneness). Remove from the skillet and let rest under foil.

In the same skillet, reduce the heat to medium, then add the shallot and garlic, sautéing until softened.

Deglaze with red wine, scraping up browned bits, and allow the wine to reduce slightly.

Stir in heavy cream and Dijon mustard, then add the crumbled Cabrales cheese. Whisk continuously until the cheese melts into a smooth sauce; season to taste and let simmer for 2 minutes.

Slice the steak against the grain and generously drizzle with the Cabrales sauce. Garnish with fresh thyme if desired.