Simple 4 ingredient mayo recipe

3/4 c grapeseed oil
1/4 c olive oil
1 egg + 1 egg yolk
2 Tablespoons lemon juice
1/2 t. salt
optional 1 t. dijon mustard if you have it
Blend the eggs, salt and lemon juice and mustard if you are using it, slowly drizzle oils while blending. I use my stick blender in a mason jar, then when its done I just cap it and put it in the fridge or use it.
source: http://www.spain-in-iowa.com/2012/01/how-to-make-homemade-mayonnaise-with-4-simple-ingredients/

If you want to be able to keep the mayo for about two months add 1 T. whey then the oils.