This recipe is from Ruby at Branches and Beads.
In the blender go one whole egg and one egg yolk along with a tsp. of dijon mustard, a tsp of salt and the juice of a lemon. Whiz this until smooth.
Then turn the blender onto maybe the second setting and leave it running~now this is the hardest part of the whole thing~you drizzle in a steady stream, the thinnest stream you can make, 3/4 to 1 cup of oil. Olive oil is fine, but don’t use EVOO, use something lighter because the flavor will really impact the final result and you don’t want it to taste to olive oil-y. I think Canola would be ideal.