Preheat oven to 400°F (200°C). Arrange bacon strips on a rimmed baking sheet lined with foil or parchment in a single layer. Bake 15–18 minutes until crisp but not burnt. Transfer bacon to paper towels to drain and cool, then chop into 1/2-inch pieces.

Prepare vegetables

While bacon cooks, trim any ragged edges from the iceberg heads. Cut each head into 2 equal wedges (quarters) or 4 if smaller heads; keep core intact on each wedge to hold leaves together. Halve cherry tomatoes (or quarter if very large). Thinly slice the red onion into rings and separate into half-moons. Place wedges on a serving platter or individual plates.

Assemble salads

Distribute tomato halves and red onion evenly over and around the lettuce wedges. Scatter chopped, crisp bacon over each wedge. Crumble blue cheese over the top, reserving a small pinch per wedge for garnish. Season lightly with sea salt and freshly ground black pepper (remember some saltiness comes from bacon and blue cheese). Sprinkle optional thinly sliced chives on top.

Dress and serve

Spoon buttermilk-herb dressing over each wedge just before serving (about 2–3 tablespoon dressing per wedge) or serve dressing on the side. Garnish with remaining blue cheese and a grind of black pepper. Serve immediately so lettuce remains crisp.

Buttermilk-Herb Dressing

In a medium bowl, whisk together mayonnaise, sour cream, and buttermilk until smooth and slightly thick but pourable.

Add the chopped parsley, chives, dill, minced garlic, lemon juice, white wine vinegar, Dijon mustard, and honey. Stir to combine.

Season with kosher salt and freshly ground black pepper. Taste and adjust: add more lemon for brightness, a splash more buttermilk to thin, or a pinch more honey if too tangy.

If possible, refrigerate the dressing for at least 20 minutes to allow the flavors to meld. Give a final stir before spooning over the wedges.