Vinaigrette

Combine and incorporate completely 1/2 teaspoon Dijon mustard with 1 teaspoon red wine vinegar.
add and incorporate one at a time 6 Tablespoons of oil.
If you add the oil all at once it won't fully incorporate and your vinaigrette will separate.
For variation you can add fresh thyme or some other spice. You can also add salt and pepper but you really don't need. If you like a more creamy vinaigrette you can add one or two Tablespoons of mayonnaise, again, incorporating gradually so it doesn't separate.
For ease of cooking I always make it in the bottom of my salad bowl and make the salad on top. But not everyone may want the same kind of dressing so you might want it separate.
This is a basic french vinaigrette and not of my own invention.