In a large bowl, combine flour, salt, eggs and water. Stir until dough has pulled together, then turn it out onto a lightly floured surface and knead until smooth and elastic. If it sticks, add a little oil to your hands. Cover with plastic wrap, and set aside in refrigerator for about 30 minutes.

Preheat oven to 350 degrees F (175 degrees C).

Place bacon in a skillet over medium heat. Cook until bacon starts to brown. Stir in chopped onion, and cook for about 5 minutes. Stir in sauerkraut, chopped apple, water, bouillon cube, salt and pepper. Reduce heat, cover, and simmer for 15 to 20 minutes. Remove from heat, and let cool.

Divide the dough into 2 portions. Lightly oil your work surface, and roll out the dough into thin sheets about 8 by 16 inches. Pour liquid from sauerkraut into a 9x13 inch baking dish, and spread bits of butter into it. Spread kraut mixture evenly over the sheets of dough. Roll sheets up widthwise. Cut slices about 2 inches wide, and place them flat and close together in the baking dish.

Bake in preheated oven for 45 minutes, or until dough is lightly browned, and liquid has evaporated.