1.   Add butter bit by bit, stirring well with a wooden spoon to incorporate.

2.   Over very low heat, whisk in butter bit by bit.

3.   Remove from heat and whisk in butter bit by bit.

4.   Remove it from heat and beat it, adding cold butter bit by bit.

5.   Season to taste with the sea salt and pepper, and then add the remaining butter bit by bit, stirring gently.