In a large wooden mortar, crush the degermed raw garlic cloves with a pinch of salt to reduce them to a smooth paste.
Add the egg yolk and a few drops of lemon juice.
Pour in the olive oil, little by little, turning constantly with the pestle or a whisk and always stirring in the same direction. The sauce should be very firm.
Pour into a bowl or leave in the mortar and refrigerate until ready to serve.