Mustard Vinegrette

1 small onion, chopped (I used yellow)
1 tablespoon mustard (I used spicy brown--also good would be dijon, stone ground, etc)
2 tablespoons sugar
1 teaspoon minced garlic
1/2 cup vinegar (I used plain--its what I had)
1 1/2 cups salad oil
3/4 teaspoon salt
1/2 teaspoon pepper

Place all ingredients in the blender and puree for awhile. The result should be a well blended dressing that doesn't separate.