In a bowl, mix softened butter, minced garlic, diced shallot, parsley, red pepper flakes, salt, pepper, and Parmesan. Shape into a log, wrap in plastic wrap, and chill until firm.
Remove steaks from the refrigerator 30 minutes before grilling to bring them to room temperature. Brush with olive oil and season with salt and pepper.
Prepare your grill: For a charcoal grill, pile coals on one side for direct heat, leaving the other side empty for indirect heat. For a gas grill, set one burner to medium-high and another to low.
Sear steaks over direct heat for 3 minutes per side. Move to indirect heat and cook to desired doneness: 130°F for rare, 140°F for medium-rare, 155°F for medium, or 165°F for well-done.
Let steaks rest for 7 minutes. Slice the chilled compound butter into rounds and top each steak before serving.