Prepare dough: Warm milk slightly. Pour milk into a large mixing bowl and add the yeast and the salt. Stir to dissolve the yeast and then add about 2 cups of the flour, stirring to make a soft dough. Cover bowl with a damp towel and let dough rise in a warm place for 30 minutes. Cut bacon into small dice while dough rises; set bacon aside. Next, cut the butter into small cubes and add to dough with remaining flour. Knead dough till smooth and let rise 40 minutes.

Prepare topping: While dough rises for the second time, heat a large sauté pan over low heat and cook bacon until fat is clear. Add sliced onions and cook until soft, translucent and bacon is slightly golden. Add caraway seeds and allow bacon mixture to cool. Next, mix the eggs and the sour cream together in a mixing bowl until smooth. Add the salt and the pepper.

Put the zwiebelkuchen together: Roll out the dough to form a 13” x 18” rectangle and place it in a sheet pan. Pat the dough in such a way that it comes up the sides of the sheet pan a little. Next, evenly distribute the onion/bacon mixture over the top of the dough. Now pour the egg mixture over the onions and bacon and spread it with a rubber spatula to completely cover topping. Place the zwiebelkuchen in a preheated 350°F oven. Bake approximately 35 minutes, or until golden brown on the top and edges and bread is done. Cool zwiebelkuchen slightly. Cut zwiebelkuchen into squares and serve warm. Makes approximately 24-36 squares.