Since it was a high of 107 today and I spent the better part of the afternoon in the pool, I wasn't super thrilled about having a ridiculously carb-heavy meal of cepelinai. Oh well.   Cepelinai are potato dumplings filled with ground pork, beef or veal. They are then drowned in a bacon, sour cream sauce. Hearty.   Although all the recipes I found called for "grated potatoes" this is a lie. If you grate potatoes then you will get fine angel-hair like strands of potatoes and they will not mix well and when boiled will fall apart. Instead, you need to pulverize the potatoes.      Ingredients:          Dumpling Mixture:   4 lbs Idaho potatoes, peeled and finely grated  pulverized  1 lb Idaho potatoes, peeled, boiled and riced  1 teaspoon salt, more or less to taste              Meat Mixture:   1 pound ground pork or 1/3 pound pork, 1/3 pound beef, 1/3 pound veal  1 medium onion, peeled and finely chopped  1 teas...