Boil the potatoes then peel them and pass them 4-5 times through a potato masher. In a bowl, work the yolks well with the sugar. Combine the mashed potatoes (cold) with the processed yolks, the softened butter, the grated lemon peel and the almond flour. Mix the ingredients, working for a few minutes with a wooden spoon. Add the egg whites whipped until stiff and where you have put a little salt. Gently incorporate the egg whites into the preparation. Grease a cake pan with oil and sprinkle with breadcrumbs (or cornmeal). Pour in the preparation, equalize everything and bake at 180 degrees for
about 1 hour.The result will be a low, golden cake with a delicious almond and lemon aroma!