Pop the eggs, mustard powder, pinch of sugar, salt & pepper in your blender and turn it on at medium speed.
Remove the funnel cup on your blender lid and start drizzling in the olive oil in a really, really slow manner (it should look as thick as a string of thread as you pour it) until it is all added to the mixture.
Add the vinegar and lemon juice… and there you have it!
*Raw eggs are not recommended for infants, the elderly, pregnant women, and people with a weakened immune system. To avoid the risk of salmonella infection, make sure you use pasteurized eggs from a source you trust—other than that, both vinegar and olive oil are known to kill bacteria.