Make the compound butter: Place the softened butter into the bowl of a stand mixer with the paddle attachment (if using a hand-held mixer, place butter into a mixing bowl) and beat until light and fluffy, 3-4 minutes. Add chives, mustard, salt and pepper. Beat on medium speed until everything is well mixed, 1-2 minutes. (is non of the equipment is available you can use mortar and pestle put will harder to combine )
Crumble in the blue cheese and gently mix until it’s incorporated
roll the compound butter into a log and refrigerate for later
preheat the grill on high for at least 15 minutes ahead of time
Remove steaks from the refrigerator 30 minutes before cooking so they come to room temperature. Season them liberally with course salt and pepper on both sides.
Rub grill grates well with oil. Grill steaks until medium rare, about 3-4 minutes per side (or however you like them done).
Remove steaks and immediately top each with a slice of Blue Cheese butter. Let it melt for 5 -7 minutes as the steaks rest