Ingredients:

1 Dijon Mustard
1/2 Dry Mustard
1/2 Salt
1 Cayenne Pepper
1 Vinegar
3/4 Olive Oil

Directions:

Put first 5 ingredients in a clean bowl and whisk until blended.
Beat in the oil drop by drop.
As the sauce thickens increase the flow of oil, but be slow and patient. The sauce, when finished will be very thick.
Taste and adjust seasonings, adding salt or vinegar if necessary.