1 tsp. prepared French Dijon mustard (the French use mild table mustard)
3 to 4 tsp. vinegar (the French use cider vinegar)
2/3 c. oil (they prefer olive oil over there)
1/2 tsp. salt (optional)
1/2 tsp. ground black pepper (optional)
1 tbsp. sugar (optional)
1 tbsp. wine (optional; you can add wine to any French recipe)

Prepare fresh several minutes before using.

Put the mustard in the bowl that you are going to whisk the dressing in. If you are using any of the optional dry ingredients, add them to the mustard. Gradually dribble in the vinegar, while whisking briskly. Keep whisking until all the vinegar has been added and you have a smooth paste. Still whisking, gradually add in the oil. You're done when you have a nice smooth emulsion. Voila! Sauce vinaigrette!

Pour over fresh salads and toss. Use as a marinade. Use as a dip. Use as a base for other sauces. Combine with mayonnaise for tuna salad, etc. Add selected spices like dill, or basil, or marjoram, or Italian spice mix, or parsley, etc. for interesting herbal editions. Sop up the leftover dressing in your salad bowl with French bread; adorn the top with a piece of cheese.