Add the white balsamic vinegar, sugar, Dijon mustard, minced garlic, salt, and pepper to a blender.
Pulse briefly or stir by hand to begin dissolving the sugar into the vinegar.
Blend on low speed for about 10 seconds to fully combine the base ingredients.
With the blender still running on low, pour the oil in a thin, steady stream through the lid opening.
Continue blending for 20 seconds after the oil is fully incorporated, until the dressing turns pale gold and creamy.
Taste and adjust with a little extra sugar or vinegar as needed, then transfer to a jar and chill for at least 30 minutes before serving.