Toast the slices of bread on both sides in a pan over medium heat.
Peel and mash the avocado with a fork and mix it with a splash of lemon juice and a little salt so that it does not turn black.
Fry the bacon in a pan with olive oil.
To make the poached egg, fill a pot with water and add a splash of vinegar. When it is boiling, remove the pot from heat and carefully add the egg. Cover the pot and let the egg poach for two to three minutes. After that, remove the egg with the help of a slotted spoon.
Assemble the plate: Put a little base lettuce, spread the bread with the avocado cream, top with bacon slices, the egg, the sauce and a few chopped chives.
Melt the butter over very low heat.
Remove the butter from the heat and with a slotted spoon and remove the foam that forms on the surface.
In a bowl, beat the two egg yolks, the lemon juice and a pinch of salt. Put the contents of the bowl over low heat and gradually incorporate the butter while beating with a whisk.