Chop the shallots and put them in a small bowl of very cold water while you prepare the rest of the vinaigrette. This will take some of the bite out of the shallot. When you are ready to add them to the vinaigrette, drain them well.
Cut the tomatoes in half, then use a flat grater or a box grater to grate the flesh into a bowl. Add the oil, vinegar, Dijon mustard, and the drained shallots. Stir to combine, then season with salt and freshly ground pepper.
Change up the flavors by adding various chopped herbs such as basil, tarragon, dill, thyme, cilantro, oregano ... YUM!
This is delicious as a salad dressing, but can also be used as a marinade for chicken or pork.