Combine the flour, salt, baking powder, sugar and butter until the mixture resembles fine breadcrumbs. Add the egg yolks. Rest the dough for at least 4 h. Roll out to a thickness of 0.5 cm and bake, in a greased oval ring mould, at 150°C (302°F) for 20 mn.
Make a light dry caramel with the sugar. Stop the cooking process by adding the hot cream, fine “fleur de sel” sea salt and butter. Leave to cool.
Combine the Sublime cream with the salted butter caramel then whip using a mixer.
Cook the sugar and water to 117°C (243°F). Add the nuts which have been warmed in the oven. Remove from the heat and toss around until evenly caramelized. Cook over a low heat to finish caramelizing. Add the butter and fine “fleur de sel” sea salt.
Pipe 10 g of salted butter caramel onto the cooked Brittany shortbread bases. Using a small Saint Honoré nozzle, pipe the whipped Sublime with salted butter caramel on top of the caramel (16 g per bar). Decorate with caramelized pecan nuts.