Special equipment: A straight-sided 3-quart tall glass bowl or four 16-ounce wide-mouth glass jars with lids
Soak the onions in ice water for at least 20 minutes. Strain.
Meanwhile, cook the bacon in a large skillet over medium heat until brown and crisp, 6 to 7 minutes per side. Remove, drain on paper towels and roughly chop.
Whisk together the blue cheese, mayonnaise, sour cream, vinegar, Worcestershire, 1/4 teaspoon salt and a few grinds of pepper in a medium bowl.
Using a 3-quart straight-sided tall glass bowl for 1 large salad or four 16-ounce wide-mouth glass jars for 4 individual salads, make a layer with a third of the lettuce, then add the following in separate layers: the tomatoes, the olives, half the remaining lettuce, the carrots, the croutons, and the remaining lettuce. Sprinkle the top with the onions and bacon. (The salad can be put together, covered and refrigerated for up to 2 hours before serving.)
If making 1 salad, just before serving, transfer it to a large bowl, toss with about half the dressing and season with salt and pepper. If making 4 salads, add dressing to each jar, season with salt and pepper, cover with the lid and shake to coat. Serve the remaining dressing on the side.
To achieve pretty, defined layers, be sure to layer more on the sides. It's OK if there isn't enough of an ingredient to fill the middle.
From Food Network Kitchen