Japanese Mayonnaise (Kewpie Mayo)

Gather all the ingredients. If you're using a blender or food processor (not hand whisking), DOUBLE the recipe. Tip: When making too small of a batch in the blender/FP, the ingredients don't have enough volume for the machine to do the work. Make sure the pasteurized egg yolk is at room temperature.In the food processor or hand mixer or immersion blender, put the egg yolk and mustard and process for 20 seconds.With the food processor running, SLOWLY drizzle canola oil (A THIN, STEADY STREAM OF OIL) until about ¼ cup of the oil has been added. The mixture is beginning to thicken and emulsify. If you add too fast, it doesn't emulsify.Add kosher salt, granulated sugar, and dashi powder and give everything a whirl again.Continue to add the oil in a thin steady stream until about ¼ cup of the oil has been added. I use "stir" while adding the oil.Finally add the rice vinegar, lemon juice, and the remaining oil and process for an extra 10 seconds, just until the ingredients are combined and emulsified. Don't blend the mayo too long as homemade mayo comes together pretty quickly in the blender. When blended too long, the emulsion that brought the spread together is more likely to break, either from overprocessing or overheating.Taste the mayonnaise and adjust with salt, sugar (I added 2 more tsp, so I used total 3 tsp), or lemon juice to your liking. You can store the mayonnaise in an airtight container for about 4 days in the refrigerator.