Cook the diced apples, water, cinnamon powder, vanilla sugar, and rosemary in a medium saucepan over medium heat for 10 minutes until softened. Remove from heat and let cool to room temperature, about 30 minutes.
In a separate bowl, beat the cream, sour cream, quark, vanilla sugar, and cream stiffener together until stiff peaks form.
In serving bowls, layer the apple compote and cream mixture alternately. Refrigerate for about 6 hours.
Just before serving, pour eggnog over each dessert.