To make the dough, combine the water, milk, sugar, yeast, and two cups of flour in a large bowl. Allow to rest for 1 hour, or until the yeast is fully active. Transfer to an upright mixing bowl with a dough hook. Add the eggs, melted butter, salt, and 4 cups of flour. Run the mixer on low for 1 minute (if the dough seems too sticky add the remaining cup flour) then turn to medium and knead for 5 minutes. Transfer to a lightly oiled bowl, cover and let rest at room temperature for about an hour, or until double in size. Preheat an oven to 350F. Transfer the dough to a floured work surface and cut into three pieces. Shape into balls, cover and let rest 20 minutes. Roll into large ovals about 1/4 inch thick. Brush with melted butter and sprinkle liberally with sugar and cinnamon. Sprinkle with cherries and walnuts. Roll into logs then shape into crescents. Transfer to baking sheets lined with oiled parchment. Brush the with the egg/milk mixture and sprinkle with poppy seeds. Make small slices about every two inches. Bake for 20-30 minutes, or until a skewer pulls out clean. Transfer to a wire rack and cool 15 minutes. Mix powdered sugar with just enough milk to make an icing the consistency of heavy cream. Drizzle over the kuchen and let dry for 15 minutes before slicing.