Use an immersion blender or food processor or blender to make this sauce

I use an immersion blender.

In a tall container, add egg yolks, dry mustard and Tabasco sauce.

Blend for a few seconds.

Heat butter in the microwave until it's completely melted, put the butter in a large enough dish so it won't spill over.

Drizzle in the metled butter while the blender is running. The sauce will thicken immediately.

Make the sauce just as you will be serving so it's hot and smooth.