Start by assembling all your ingredients on the countertop.

In your blender or food processor, combine the egg, Dijon mustard, and white wine vinegar.

Blend the mixture on medium speed for about 20 seconds until well combined.

With the blender still running, slowly drizzle in the vegetable oil.

Continue blending until the mayonnaise thickens and becomes creamy, which takes about 30 seconds to a minute.

Once your mayonnaise reaches the desired consistency, season it with salt to taste.

Transfer the mayonnaise into a storage jar using a spatula.

Refrigerate the mayonnaise for at least 30 minutes before serving.