Ingredients
1 c olive oil
2 tsp vinegar
1/2 tsp mustard powder
1 egg
1/2 tsp each of salt and pepper
Method
Place the egg, seasonings and vinegar in a blender and blend on medium speed for a few seconds.
Still on medium speed, add oil drop by drop to begin with, through the lid, and then in a thin and slow stream as the mixture thickens.