Wedge Salad

Cut 4 ounces slab bacon into 1"-thick pieces and cook in a medium skillet over medium-low heat, stirring often, until crisp, 5-7 minutes; transfer to a paper towel-lined plate. Whisk 1/2 finely chopped small shallot, 3/4 cup sour cream, 1/2 cup buttermilk, 1 tablespoon chopped fresh chives, and 1 tablespoon white wine vinegar in a small bowl; fold in 1/2 cup crumbled mild blue cheese. Adjust consistency with sour cream or buttermilk, if needed. Season dressing generously with kosher salt, freshly ground black pepper, and more vinegar, if needed. Cut 1 small head of iceberg lettuce into 4 wedges; place on plates and spoon dressing over. Top with bacon, 1/4 thinly sliced small red onion, and more crumbled blue cheese and chopped chives.