Tabbouleh is a parsley salad, not a bulgur salad. It is important to use quality, flat-leaf parsley and you can use the tender parts of the stems as well, but discard the thick ones.
A very sharp knife should be used for fine chopping. Using a food processor will ruin the texture and create a pulpy, soggy salad.
Rinse the bulgur and place it in a small bowl. Pour 0.5 cup of hot water over it and cover. Let stand for 20 minutes until the bulgur absorbs the liquid and softens.
After soaking, drain any excess liquid. For an authentic dry texture, you can gently squeeze the bulgur in a sieve to remove as much water as possible.
Wash the parsley and mint thoroughly and, most importantly, dry them completely (preferably in a salad spinner). Moisture would water down the salad.
Using a very sharp knife, chop the parsley and mint into the smallest possible pieces. This is the most important part, take your time. Parsley must dominate the volume.
Peel the tomatoes and remove the watery part with the seeds. Dice the remaining flesh into very small cubes. Finely slice the scallions.
In a large bowl, combine the chopped parsley, mint, tomatoes, scallions, and the soaked bulgur.
Add the lemon juice and olive oil. Season with salt and freshly ground black pepper.
Mix the salad gently but thoroughly. Be careful not to bruise the herbs. It is best to use two spoons and 'toss' the salad.
Allow the Tabbouleh to rest in the refrigerator for at least 10 minutes to allow the flavors to meld.
Serve chilled, often on a platter lined with romaine lettuce leaves, which are used as scoops for the salad.