This light yet impressive salad is ideal for a potluck or any large gathering; assemble it up to 4 hours in advance.
Cook bacon in a large skillet over medium heat until browned and fat is rendered, 10 to 15 minutes. Transfer to paper towels to drain and crisp.
Meanwhile, in a food processor, combine buttermilk, avocado, lemon juice, and oil; season generously with salt and pepper. Puree until smooth.
Lightly pack iceberg into the bottom of a large glass bowl or trifle dish. Arrange egg slices vertically along edge of bowl in a single row, then scatter remaining eggs evenly over lettuce. Layer cabbage over eggs, then tomatoes. Season tomatoes with salt, then top with peas. Pour dressing over peas and spread into an even layer using a spatula. Top with cheese and bacon. Refrigerate until ready to serve.