When you make Italian dressing, you want to make it better than what you get in a bottle. Commercial Italian, although convenient and, if you buy a quality brand, not bad tasting, can't match a well-made homemade Italian. It all starts with a basic vinaigrette -- 1 part vinegar to 3 parts oil -- and ends with your finishing touch. Build upon the basic Italian herbs marjoram, rosemary, oregano, thyme and basil with aromatics, such as shallots, and pungents, such as minced garlic, and you'll beat the bottle every time.
Add vinegar to a mixing bowl. Commercial Italian dressings use regular white distilled vinegar, but you can use any flavored vinegar you like. Red wine and white wine vinegar both make good bases for an Italian dressing. You need 1 tablespoon of vinegar to make 1/2 cup of dressing.
Add a pinch of salt to the vinegar and let it sit for a moment to melt. Pour three times as much oil as vinegar into a measuring cup. Flavored oils, such as olive and basil, add a layer of flavor that sets homemade Italian dressing apart.
Add a few drops of oil while vigorously whisking the vinegar to start the emulsion. Continue to whisk while slowly drizzling in the remaining oil in a steady, slow stream.
Taste the vinaigrette and adjust the seasoning as needed with salt and pepper.
Add freshly chopped herbs and spices to the vinaigrette. Classic Italian seasoning mixes usually contain rosemary, thyme, basil and oregano as the base herbs. You can add those and take it further with some sage and parsley, or pick two or three of the base herbs and add minced roasted garlic, finely chopped shallots and fennel seeds.
Transfer the Italian dressing to a glass jar and let it sit in the refrigerator for a couple of hours to marry the flavors. Shake the jar vigorously to re-emulsify the dressing right before serving.