This is so much easier than I thought. I made it the first time for this Easter and I think the next time I'll keep it in a small slow cooker to keep it warm.
It's so good you could put it on anything: eggs, roasted vegetables, chicken, ice cream, dog food, whatever........
In a blender:
3 egg yolks
1/4 teaspoon Dijon mustard
1 Tablespoon lemon juice
1 dash hot pepper sauce like Tabasco (which I didn't have so I used a pinch of crushed red peppers)
melt in the microwave
1/2 cup butter (1 stick) in a measuring cup
blend the first section to get it all blended
slowly add the butter in a thin stream. It should thicken almost immediately The recipe I read said you can keep it warm by keeping the blowl in a larger bowl of hot tap water. But I'm still going to try the slow cooker.