This is my standard vinaigrette recipe. It's especially good on salads which involve some sweet element (apples, pears, raisins, cheese). If I'm in a hurry, I pour in a small amount of onion powder and/or garlic powder. Not as good, but still better than most store bought dressings! I nearly always use dried oregano as my herb of choice.
From America's Test Kitchen Family Favorites Cookbook
3/4 c. olive oil
3 T. red wine vinegar
2 t. minced shallot or red onion (I often just use yellow onion)
2 t. Dijon mustard (optional--I never use)
1 1/2 t. minced fresh tarragon, dill, basil, or oregano or 1/2 teaspoon dried
1 garlic clove, minced
1/2 t. salt
1/4 t. pepper
Combine all ingredients in a jar and shake! (Cover tightly before shaking) Keeps a week or so in the fridge--bring to room temperature before using (I've sometimes stuck the jar in a bowl of hot water to help it warm up faster).
Makes about 1 cup