How to bake classic French butter cookie - Palet Breton

Hello dear friends, what a beautiful, beautiful day! Welcome to class. Today we learn to make the very classic French butter cookie - Palet Breton from scratch. 
 
In this class, we will make the cookie  from scratch using your everyday household equipment. You do not need fancy tools. As long as you understand how it works, you can make healthy, clean and delicious Palet Breton at home. 
I will demonstrate the step by step process, explain the appropriate measurements, guide you to different kinds of tricks and techniques, show you how to make, rest and cut the dough, bake in the right temperature. At the end, we will discuss making good from failed cookies. 
Here is the recipe:
 
Ingredients:
150 g unbleached all purpose flour
120 g unsalted butter
100 g sugar
3 large egg yolk
Pinch of salt
½ teaspoon baking soda
Preparation: 
Heat the butter in the microwave oven for 30 seconds so it is soft but not too liquidy. 
In a large bowl, mix butter, sugar, egg yolk and a pinch of salt until they become homogeneous. 
Add flour and baking soda to the mixing bowl through a fine mesh sifter gradually. 
Briefly combine all ingredients till there is no clump. 
Put the dough in a plastic bag and leave it in the refrigerator for at least 3 hours.
Baking:
Preheat oven to 340℉ or 170℃.
Take the cookie dough out of the refrigerator and roll to 10mm or ½ inch thickness. Use baking rings to cut the dough then bake inside them. You can use silicone cookie molds to keep their shape.
Bake for 15 minutes, or till the cookies are golden.
Let cookies cool off before taking them out of the rings or molds. 
Sprinkle some salt before serving.