Step 1

Arrange two racks in the oven, one in the middle and one in the upper third, and heat the oven to 400°F. Meanwhile, line a rimmed baking sheet with aluminum foil. Quarter 1 cup cherry tomatoes. Mince 1 small shallot (about 2 tablespoons). Finely chop until you have 2 tablespoons fresh chives. Finely grate 1 1/2 ounces Parmesan cheese (about 1/2 cup).

Step 2

Juice 1 medium lemon (about 3 tablespoons) into a medium bowl. Add 1/2 cup of the crumbled blue cheese and mash with the back of a fork to create a smooth paste. Add 1/4 cup sour cream, 1/4 cup mayonnaise, 2 tablespoons olive oil, 1 teaspoon Dijon mustard, 1/2 teaspoon kosher salt, and 1/2 teaspoon black pepper. Mix thoroughly until combined. Refrigerate while you cook the bacon.

Step 3

Place 4 strips bacon on the prepared baking sheet in a single layer. Bake on the middle rack until deep golden-brown and crispy, 15 to 20 minutes. Meanwhile, quarter 1 medium head iceberg lettuce through the core to make 4 wedges. Cut the core out from each wedge.

Step 4

Remove the bacon from the oven and let cool for 5 minutes. Set the oven to broil. Chop the bacon into bite-sized pieces. Discard the bacon grease and foil, then cover the baking sheet with a new sheet of foil.

Step 5

Place the lettuce wedges cut-side up on the baking sheet. Brush the cut sides of each wedge with some dressing. Sprinkle with the Parmesan cheese. Broil on the top rack until the cheese is melted and the lettuce is browned on the edges, rotating the baking sheet halfway through, 2 to 3 minutes total.

Step 6

Transfer the wedges to a serving platter. Top with the remaining 1/2 cup blue cheese, bacon, cherry tomatoes, shallots, chives, and a few grinds of freshly ground black pepper. Serve with the remaining dressing.