Creamy Dijon-style mustard emulsifies better than the grainy, whole seed type, so use creamy if you can.
This recipe is courtesy of The Old Farmer's Almanac Comfort Food cookbook. Click here for more delicious recipes!
Combine the vinegar, mustard, garlic, and brown sugar in a bowl and whisk well. Add the olive oil in a slow, steady stream, while whisking. Add the salt and pepper, to taste, continuing to whisk.
Note: Alternatively, combine all of the ingredients in a small jar with a tight lid and shake it vigorously. Taste and adjust the seasonings, if desired.