Galettes Bretonnes - Britanny Butter Biscuits 
 
Galettes Bretonnes are a classic French butter biscuit from Brittany, region of France (Bretagne in French) known for their rich flavour and delicate, sandy crumb. Made with plenty of butter, they’re simple, golden, and melt-in-the-mouth.

Ingredients :
180 g / 12 tbsp salted butter - This cookie is specifically made with salted butter rather than unsalted which is typical for cooking recipes from the Brittany region of France.
2/3 cup caster sugar or 130 g / superfine sugar 
1 egg yolk, from large eggs (55 g each in shell), at room temperature 
1 tsp vanilla extract
250 g all-purpose flour
Egg wash : 1 egg yolk and 1 tsp milk
 
Method :
BISCUIT DOUGH
This is one of those biscuits where the dough is rolled out thinly, biscuits cut out using a round cutter then baked. The dough is easy to work with but once you cut the rounds out, handle them gently using a spatula to move them onto the trays.
Using an electric beater on medium low speed, beat the butter in a bowl for about 30 seconds until smooth. Add the sugar then beat on medium for about 1 minute until the butter becomes pale in colour.
Add the egg yolk and vanilla, then beat just until combined then stop beating.
Add flour in 3 batches : Add one-third of the flour and mix in with the beater on medium low speed. Then add half the remaining flour, mix in again with the beater, then beat in the remaining flour. It will resemble wet sand.
Bring dough together : Turn the mixture out onto the counter, then push the mixture together into a mound.
Knead into ball : Use your hands to knead the dough so it comes together into a smooth ball.
 Wrap the dough in cling wrap and refrigerate for 1 hour.
  1. Roll out dough – Put the dough between 2 sheets of baking paper (parchment paper) then use a rolling pin to roll the dough out to 5 mm thickness(not too thin or it will burn). It doesn’t matter what shape it is as long as you get the right thickness.
  2. Cut out biscuits – Use a 7cm round cookie cutter to cut out rounds and use a spatula to transfer to lined baking trays (you will need 2 trays).
  3.  Gather the dough scraps and re-roll out and continue cutting out cookie rounds. You should get 24 cookies in total.
  4. Whisk the egg yolk and milk and brush onto the surface of each biscuit.
  5. Place 2 trays in the oven and bake for 15 minutes at 180°C ot 160°C fan-forceds until they are light golden. 
  6.  Leave on the trays for 5 minutes, then transfer to a rack to cool completely.

( I have seen and cooked this recipe from recipetineats.com a famous blog by Nagi and Chef JB)