Аdd egg yolk and a little water if needed and mix to a firm dough. Knead the dough briefly and gently on a floured surface. Wrap in cling film and chill in the fridge for 30 min. Dust the work surface lightly with flour. Put pastry on it and sprinkle a little flour on top. Roll it to a circle and 5 mm thick. Place it in a tart tray and push the ends with fingers. Trim the edges. Put baking paper and baking stones on top. Bake until lightly golden brown.

Make the pastry creme. Pour sugar and milk into a medium saucepan and heat to just before boiling point, over medium heat. In a bowl mix the rest of the ingredients without butter and add little milk at the time to warm up the mixture. Retune into the saucepan on cooк over medium heat stirring constantly until thick and smooth. Remove from the heat and add butter. Cover with cling film to prevent forming a skin.