Pre-heat gas grill to 350F or traditional grill to medium heat or grill pan to medium-high heat. Bush the halved romaine hearts with olive oil on both sides and season with salt and pepper.
While the grill is heating whisk together remaining ingredients, except the blue cheese, and season with salt and pepper.
Place the halved romaine cut side down on grill. Grill for 1-2 per minutes on each side.
Remove from grill to serving platter and sprinkle with blue cheese and drizzle with the vinaigrette. Serve immediately.