Pour the oil over top.

Place the immersion blender at the very bottom of the jar.

Blend without moving the blender for 10–15 seconds, until a thick white mayonnaise forms around the blade.

Slowly lift the blender to incorporate the remaining oil.

Continue blending until smooth, thick, and creamy.

Taste and adjust seasoning to your liking.

In a medium bowl, whisk together the egg yolks, Dijon mustard, salt, sugar, MSG, and rice vinegar until smooth.

While whisking constantly, add the oil a few drops at a time until the mixture begins to thicken and emulsify.

Once emulsified, slowly drizzle in the remaining oil in a thin, steady stream while whisking continuously.

Continue whisking until all of the oil has been incorporated and the mayonnaise is thick, smooth, and glossy.

Taste and adjust seasoning as needed.

Add the egg yolks, Dijon mustard, rice vinegar, apple cider vinegar, sugar, salt, and MSG to the bowl of a food processor. Process for 10-15 seconds until smooth and well combined.

With the food processor running, very slowly drizzle in the oil through the feed tube. Start with just a few drops at a time until the mixture begins to emulsify.

Once the mayonnaise starts to thicken, gradually increase the oil to a thin, steady stream while continuing to process.

Continue processing until all of the oil has been incorporated and the mayonnaise is thick, smooth, and creamy.

Taste and adjust the seasoning if needed.