Keto Steak with Blue Cheese Sauce

Heat a grill pan over high heat. Season filet mignon steaks with salt and pepper. Cook steaks in the hot pan until beginning to firm and hot and slightly pink in the center, about 4 minutes per side for medium. An instant-read thermometer inserted into the center should read 140 degrees F (60 degrees C). Set aside.

Mix olive oil and butter in a pan over medium heat and allow butter to melt; add onion. Cook and stir until softened and browned, 5 to 7 minutes. Add heavy cream, blue cheese, onion, garlic, nutmeg, and pepper. Reduce heat to medium-low; stir until cheese melts completely, 3 to 5 minutes more. Add a little water to thin if necessary. Pour sauce over the steaks.