Pat the steaks dry with a paper towel to remove excess moisture. Brush them lightly with olive oil and season generously with salt and ground black pepper on both sides.Preheat a large cast iron skillet or grill over medium-high heat. Cook the steaks for 4-5 minutes on each side until browned and cooked to your preferred doneness. Transfer to a warm plate and set aside.In the same skillet, melt 2 tablespoons of butter. Add the shrimp, season with salt and pepper, and sear until pink and just cooked, about 2 minutes. Transfer the shrimp to a bowl and set aside.Deglaze the skillet with a small amount of chicken broth, then add the remaining broth and heavy cream, bringing it to a gentle simmer. Add the Boursin cheese and stir until it melts into the sauce. Stir in the Dijon mustard and let the sauce simmer for a few minutes to thicken. Season with salt and pepper.Return the shrimp to the pan, sprinkle with parsley, and stir to combine. Serve alongside the steaks.