Preheat your oven to 400°F (200°C). Place the bone marrow bones upright in a roasting pan and roast in the oven for about 15-20 minutes, or until the marrow is soft and begins to separate from the bone.

Remove the bones from the oven and let them cool slightly. Scoop the roasted marrow into a bowl and mix it with the softened butter. Season with salt and pepper to taste. Set aside.

Pat the ribeye steaks dry with paper towels. In a small bowl, combine the Herbes de Provence and sea salt. Rub the mixture all over the steaks.

Heat a large cast-iron skillet or heavy-bottomed pan over medium-high heat. Add the olive oil and heat until shimmering.

Carefully place the ribeye steaks in the hot skillet. Sear for about 4-5 minutes on each side for medium-rare, or until they reach your desired doneness. Use a meat thermometer for accuracy (medium-rare is about 130°F or 54°C).

Once cooked, remove the steaks from the skillet and let them rest for 5-10 minutes.

Slice the ribeye steaks against the grain. Serve topped with a generous dollop of the roasted bone marrow butter and garnish with chopped fresh parsley.