Quick and Easy BLT Salad with Pickled Onions

Ingredients

• 1 small red onion, thinly sliced
• 1/4 cup plus 1 tablespoon cider vinegar, divided
• 1/4 cup boiling water
• 2 teaspoons honey
• 1/2 teaspoon kosher salt, divided
• 6 slices thick-cut bacon, cut into 2-inch pieces
• 4 slices sourdough bread, cut into 1-inch cubes
• 1/4 cup mayonnaise
• 6 tablespoons buttermilk
• 2 tablespoons vegetable oil
• 1 head romaine lettuce, cut into 1-inch pieces
• 2 cups halved cherry tomatoes