Make the blue cheese dressing: Add the Greek yogurt, buttermilk, white wine vinegar, Worcestershire sauce, salt, pepper, and half of the blue cheese to a blender or food processor. Blend until smooth and creamy. Transfer to a bowl or jar and stir in the remaining blue cheese and chopped chives. Add another splash of buttermilk if needed to reach a thick but pourable consistency. Cover and refrigerate while you prepare the salad.
1 cup whole-milk Greek yogurt, 1/3 cup buttermilk, 1 Tablespoon white wine vinegar, 1 teaspoon Worcestershire sauce, ½ teaspoon kosher salt, ¼ teaspoon black pepper, 3/4 cup 3 ounces crumbled blue cheese, 2 Tablespoons finely chopped fresh chives
Prep and season the steak: Remove the steak from the refrigerator 30 minutes before cooking if you can for the best steak sear. Pat it very dry with paper towels and season generously on both sides with kosher salt and freshly ground black pepper.
1 1/2 pounds ribeye steak, Kosher salt and freshly cracked black pepper
Sear the steak: Heat a large cast-iron skillet over high heat for 2-3 minutes, until very hot. Turn on your vent fan because the skillet will likely smoke. Add enough avocado oil to lightly coat the bottom of the pan. Sear the steak undisturbed for 3–4 minutes, until a deep golden-brown crust forms. You can gently press down in the center and edges to help it lay flat. Flip and cook for another 3–4 minutes, or until an instant-read thermometer inserted into the thickest part reachs 125°F for medium-rare or 135°F for medium. Cook time will vary depending on the thickness of the steak. Transfer it to a cutting board and let it rest for 5-10 minutes while you assemble the salad.
1-2 Tablespoons avocado oil
Assemble the salad: Add the chopped romaine to a large serving bowl or platter. Drizzle with a few tablespoons of blue cheese dressing and toss until the leaves are lightly and evenly coated. Arrange the cherry tomatoes and red onion. Cube or thinly slice the steak and add to the salad. Scatter the blue cheese crumbles and plenty of chopped chives over the top.
1 head romaine lettuce, 1 pint cherry tomatoes, 1/2 medium red onion, 4 oz blue cheese, Finely chopped fresh chives to taste
Drizzle the remaining blue cheese directly over the steak and salad. Finish with freshly cracked black pepper and more chopped chives.