In a blender or food processor, combine the black garlic, fresh garlic, and shallot, and blend as finely as possible. Add the red wine vinegar, mustard, and agave nectar, and again blend to combine.
Add olive oil in a steady stream, blending until smooth. Season with salt and pepper to taste (this will need plenty of salt), and add more oil if needed to reach the desired texture. After adding additional oil, check the seasoning one more time for salt, pepper, and acid.
Enjoy right away, or store in the fridge for up to a week or more. The mustard and black garlic help this dressing emulsify quite well, but if needed, shake/stir the dressing again before serving.
LOWER-FAT VERSION: I have it on good authority that you can substitute part of the olive oil with aquafaba (the cooking liquid from chickpeas or other beans) to make a lower-fat dressing.NUTRITON: Serving size is approximate. Calories per tablespoon depend on the final amount of oil, vinegar, etc. used.WHERE TO FIND BLACK GARLIC: Sometimes you just have to get lucky! Trader Joe's has been known to sell it at times. Other natural/specialty grocers tend to carry it seasonally. I've linked to black garlic on Amazon above, but note that the price online is WAY WAY higher (~$15 or more) than what I paid in the store (~$4).