In a measuring cup or small bowl, combine all the dressing ingredients. Whisk until the mixture is smooth and emulsified. Set aside.
Place the chopped romaine lettuce evenly in a large serving bowl or platter.
Arrange the chicken slices, crumbled bacon, hard-boiled egg quarters, avocado slices, halved cherry tomatoes, thinly sliced red onion, and crumbled blue cheese on top of the lettuce.
If the dressing has separated, give it a quick whisk to combine it again. Drizzle a small amount of dressing over the salad to start. Be careful not to add too much at once. This recipe makes enough dressing for 2-3 salads, so add it gradually and taste as you go.
Serve the salad right away. Store any leftover dressing in the fridge for up to one week.