1 egg (room temp)
1 teaspoon dry mustard
1 teaspoon salt
1 1/4 cup vegetable oil
dash cayenne pepper
3 tablespoons lemon juice or vinegar

Place egg, mustard, salt, cayenne pepper and 1/4 cup oil in blender and blend on low.
While the machine is blending, SLOWLY pour in another 1/2 cup oil.
You may have to stop and scrape down the mayo.
Add the lemon juice/vinegar and the remaining 1/2 cup oil.
Blend until well combined.
Store in refrigerator.