Dressing

1. Add the white vinegar, sugar, diced onion, paprika, dry mustard, celery salt, and kosher salt to a blender. Blend well until fully combined.
2. With the blender running, slowly drizzle in the oil until emulsified. Pour into a container and set aside. Whisk before using.

Ingredients

1. Preheat the oven to 350F. Lay the bacon out in one even layer onto a foil-lined sheet pan. Cook the bacon until crisp, about 25-30 minute. Transfer the bacon to paper towels and let cool. Crumble into bite-size pieces.
2. Meanwhile, preheat the grill over high heat. Toss the chicken breasts with enough oil just to coat and season them with a generous pinch of salt.
3. Grill the chicken breasts by placing them on the hottest part of the grill. Sear on the first side until nice grill marks appear, then flip the chicken over. Once seared on the second side, transfer the chicken to a warm part of the grill, cover the grill top, and finish cooking through (about 6-10 minutes; all chicken breasts will cook differently depending on their thickness).
4. Transfer the chicken to a plate and cover loosely with foil to let rest for about 5 minutes.
5. Meanwhile, toss the heads of romaine with a little oil and season with a generous pinch of salt. Grill the romaine, keeping the root intact, just until it’s charred on all sides and slightly tender (only about 2 minutes total).
6. Cut the chicken into thin slices and roughly chop the charred romaine.

Assembling

1. In a large mixing bowl, combine the romaine and arugula.
2. Add the bacon, avocado, cherry tomatoes, radishes, crumbled blue cheese, and hard-boiled eggs, saving a little of each ingredient to use for garnish.
3. Add the dressing to the bowl little by little, tossing gently until the ingredients are well coated, but not drenched (save any extra dressing; you most likely will not need to use it all).
4. Taste the salad and season with salt as needed.
5. Plate the salad on a large platter or serving bowl. Arrange the chicken over top. Garnish with the reserved ingredients and a generous sprinkle of chives. Drizzle a little bit more dressing to finish.