Prepare the crispy Sarrazin caramel: heat the caramel until it softens, then add ground Sarrazin seeds in a blender. Set aside to infuse. Put the Beurre Bordier au Sarrazin in a bowl and melt in the microwave or bain-marie. Add the sugar, then the almond powder and flour.
Cover a large, flat plate with cling film and place in the freezer. Using a vegetable peeler, cut 40 shavings of Beurre Bordier au Sarrazin, then place them on the cling-film plate (if your butter softens too quickly, return it to the freezer and repeat the operation). Keep them on the plate, in the freezer.
Preheat oven to 210°C. Pour the flour and sugar into a bowl. Add the butter in small pieces and mix well until the dough resembles breadcrumbs.