Place the egg yolks, mustard, cayenne, and salt in a measuring cup, wide-mouth mason jar, or blender canister and blend to combine.
With the blender still running, slowly pour the HOT melted butter into the egg mixture.
Keep the sauce warm until ready to serve.
HOW DO YOU FIX A BROKEN SAUCE?When emulsifying sauces things are bound to go wrong especially from overbeating or adding the butter too quickly. Simply blend in a teaspoon or two of boiling water, a drop at a time. If that doesn’t work, slowly add in a beaten egg yolk. This should tighten up the sauce and pull it back together.CAN YOU MAKE HOLLANDAISE SAUCE IN ADVANCE?Yes!! Once your sauce has cooled to room temperature, place it in the refrigerator until ready to use. Reheat in the microwave in 10 second increments stirring in between , until warm but not hot….you don’t want to break your sauce at this point!