Whisk everything but the oil. In a 1.5 quart bowl, whisk together the mustard, salt, egg, and vinegar.
While whisking, drip in 2 to 6 drops of olive oil.
Add 10 drops olive oil. While whisking like mad, add a bit more olive oil.
Drizzle in the canola oil. Are you whisking? Good. Now slowly drizzle in about a cup of canola oil. Start slowly at first, and gradually increase the rate of flow. NEVER stop whisking while you add the oil.
Add more oil. We added about 1/3 cup split evenly between olive and canola oil.
Again, drizzle it in while whisking. Now the mayonnaise should really thicken up.