Season the steaks evenly with ½ teaspoon salt and ¼ teaspoon pepper. Allow the steaks to stand at room temperature for 15 to 30 minutes before grilling.
Prepare the grill for direct cooking over medium-high heat (200º to 260ºC). If you're using a charcoal grill, keep a small part of the charcoal grate clear of briquettes as a safety zone of indirect heat.
In a small bowl whisk the buttermilk, yogurt, chives, lemon juice, ¼ teaspoon salt, and ⅛ teaspoon pepper. Stir in the blue cheese. Set aside.
Brush the tomatoes and onion slices with the oil and season evenly with salt and pepper. Grill the tomatoes and onion slices over direct medium-high heat, with the lid closed, until the tomatoes are blistered (don’t worry if the tomato skins slip off) and the onion is tender, turning occasionally. The tomatoes will take 6 to 8 minutes and the onion will take 8 to 10 minutes. Remove from the grill as they are done. Cut the onion slices in half.
Brush the tomatoes and onion slices with the oil and season evenly with salt and pepper. Grill the tomatoes and onion slices over medium-high heat, with the lid closed, until the tomatoes are blistered (don’t worry if the tomato skins slip off) and the onion is tender, turning occasionally. The tomatoes will take 6 to 8 minutes and the onion will take 8 to 10 minutes. Remove from the grill as they are done. Cut the onion slices in half.
Related Grill Skills
Slicing an Onion
Grill the steaks over direct medium-high heat, with the lid closed, until cooked to your desired doneness, about 8 minutes for medium rare, turning once or twice (if flare-ups occur, move the steaks temporarily over indirect heat). Remove from the grill and let rest for 3 to 5 minutes. Cut the steaks into thin slices.
Grill the steaks over medium-high heat, with the lid closed, until cooked to your desired doneness, about 8 minutes for medium rare, turning once or twice (if flare-ups occur, move the steaks temporarily over indirect heat). Remove from the grill and let rest for 3 to 5 minutes. Cut the steaks into thin slices.
Place an iceberg lettuce quarter on each of four serving plates. Top with equal amounts of the dressing and divide the steak, tomatoes, and onion among the plates. Serve immediately.