Mayonnaise with Avocado or Raw Egg

2 ripe avocados OR 2 raw egg yolks
2 Tbsp. lemon juice
2 Tbsp. Dijon mustard (optional)
¼ Tbsp. sea salt
10 Tbsp. (1 cup) extra virgin olive oil, added in a steady stream until the mixture is thick like mayo

Except for the olive oil, mix all the ingredients together in a blender and puree into a nice paste.
Very slowly, with the blender running, add olive oil in a stream and blend until thick.
You may need to add more oil to get the desired consistency.