Buckwheat Flour Focaccia with Grapes, Roquefort, and hazelnuts.

Boil the potato with the peel, when it is tender, drain it, and pass it through the potato masher without peeling it, letting the pulp fall back into a bowl. Put the yeast in a small bowl with the sugar and 50 ml of warm water and let it rest for 5-10 'until it forms a foam. Pour the flour on the work surface, add the mashed potato, oil, salt, pepper, and yeast in the center and start kneading, adding, little by little, the remaining water until you obtain a homogeneous and elastic dough that doesn't stick to your fingers. If necessary, add a little flour or a little water. The variables also depend on the type of potato used. Preheat the oven to 200 degrees. Grease an enameled pan with oil or line it with baking paper and grease the paper. Roll out the focaccia with your hands forming a rectangle with a thickness of 1 cm of about 25 x 30 cm. With your fingertips, dimples in the dough, mix 2 tablespoons of oil with 2 of water, and spread them on the focaccia. Bake for 12-15 minutes. Meanwhile, wash the grapes and drain them well, shell them, and cut the larger berries in half. Also, cut the hazelnuts in half. Remove the focaccia from the oven, crumble the Roquefort over the entire surface, distribute the grapes and hazelnuts over it, and put the focaccia back in the oven for another 10-15 minutes until the edges are slightly golden. Let the focaccia cool for a few minutes before cutting and serving it.