Make a roux in a large saucepan by melting the butter and stirring in the flour; cook for 2 minutes. Add the stock and simmer until smooth. Add the cream and cheese and bring to a boil. Stir thoroughly and then add the trout fillets and reduce the heat. Simmer gently for 3 minutes. Whisk the eggs, wine, and kirsch together, add to the soup, and simmer for a few minutes.