Warm Amaretto. Set aside 2 Tbsp of cranberries for garnish. Pour Amaretto over the remaining cranberries and set aside. Melt butter and let it cool. Beat eggs with yogurt, sugar, and vanilla sugar. Add butter. Mix flour with baking powder and stir into batter. Cut apples into quarters, peel, remove core, and chop into small pieces. Chop walnuts (set some aside for garnish). Cut Amaretti biscuits in half. Add cranberries, apples, walnuts, and Amaretti biscuits into batter.