Preheat oven to 375 F. Grease and flour a cookie sheet.
In a mixer, place flour, butter, milk and sugar and mix with the paddle attachment until blended, about 1 minute. Add almonds, walnuts, baking powder and kirsch and eggs and blend 1 more minute. Turn dough out on to a board and knead 30 seconds until slightly firm. Form into round and place on a baking sheet. Brush with remaining beaten egg and bake 25 to 30 minutes until light golden brown. Allow to cool before serving.
Recipe Courtesy of Mario Batali