1 1/2 tbsp mustard (made with distilled white vinegar)
1 cup olive oil (extra-light tasting)
1/2 tsp salt
Place egg, mustard, oil, and salt into a mason jar and stick an emulsion blender all the way to the bottom, emulsify.
Once the bottom portion is emulsified, slowly bring the blender up and blend until the next portion is emulsified, going up and down as necessary to create a homogenous mixture. Continue until the mixture is creamy throughout, 1-2 minutes.