Make the cowboy butter: melt the butter in a stainless steel pan over low heat. Whisk in the paprika, cayenne, chili flakes, garlic, Dijon, chives, parsley, lemon zest and juice, salt, and pepper until combined. Remove from heat and hold at room temperature.
Season the ribeye pieces heavily with salt and pepper. Sear on all sides in a hot stainless steel pan until well browned.
Remove the steak from the pan and toss to coat in the cowboy butter.
Serve with mashed potatoes and caramelized or fried onions.