Sift the Kamut flour with the powdered sugar onto the working surface and distribute the COLD butter pieces on top. Add the egg, salt, vanilla, lemon zest, and lemon juice and knead into dough. Cover with plastic wrap and cool in the refrigerator for several hours.
For the poppy seed filling, bring the milk, butter, sugar and lemon zest to a boil, add the poppy seed, cinnamon, crumbs and raisins and bring again to a boil; let cool. Wash, dry and peel the Granny Smith apples, then core and lice them into thin wedges. Sprinkle with lemon juice. Roll the dough out to about 4 mm (1/6 in) and line the bottom and sides of the form with part of the dough; prick with a fork. Fill alternating the poppy seed mixture and the apple wedges. Cover with the remaining dough and prick a decorative pattern into the top with a fork.
Brush with egg yolk and bake in a preheated 180°C (360°F) oven for about an hour. Remove from the oven and let cool in the form. Remove from the form and let rest at least two hours before serving.