This recipe was taken from the book Cooking the Austrian Way.

Ingredients:

1 pound sour apples, granny smith
2 Tblsp sugar
1 lemon
1 cup sultanas
1 cup currants
1 or 2 Tblsp cornflour
1 Tblsp butter
1 cup white wine

Core the apples, then cut up into small pieces and place in a large saucepan. Grate the lemon rind over them. Cook the apples until soft, then press them through a seive into a bowl and then return them to the saucepan. Add 4 pints of water, the sugar, currants and sultanas. Simmer gently for 30 minutes.

In a small saucepan, melt the butter then add the cornflour, stirring untilsmooth. Gradually add the mixture to the soup, while stirring. Simmer for another 10 minutes and then serve.