This vinaigrette differs from the standard balsamic vinaigrette by addition of water which has the effect of emulsifying (thickening) it. This is useful where you want the dressing to cover more evenly.
1 tsp Dijon mustard
1 tablespoon balsamic
1 tablespoon cold water
4 tablespoons (60ml) extra virgin olive oil
Freshly ground black pepper
Squeeze of lemon juice (optional)
Whisk together the mustard, balsamic and water, then whisk in the oil. This should give a thick, glossy dressing. Season with salt and pepper. Taste and add lemon juice if necessary for extra acidity (whether or not you need this will depend on the sweetness of the balsamic).
This dressing will keep for up to a week in the fridge.