Transfer dough to baking dish and sprinkle with almonds. Spread apple slices on top, then sprinkle with sugar mixture. For the crumble, combine flour, remaining sugar, butter, salt, and vanilla sugar and use your fingers to combine into large crumbs. Sprinkle crumble over apples and bake at 180°C/350°F for approx. 45 min. Remove from oven and let cool. Cut into squares and enjoy!