Combine salt, pepper, rosemary, thyme, and coffee. Evenly season steaks with the rub. Cut the roots off the onion while leaving the core intact. Cut into quarters from the root end to the top. Drizzle onion and tomatoes with olive oil.

Preheat the grill for steaks and onions. Grill steaks over medium-high heat for 5 minutes per side and finish over indirect heat until steaks reach an internal temperature of 125°F for medium rare. Rest at least 5 minutes before serving. Grill onions on two sides for 5 minutes on each cut side, then finish over indirect heat while lying on the skin side.

Grill tomatoes over high heat for 1 to 2 minutes or until skins are blistered.

Serve steaks with grilled tomatoes and onions.