Mom's Famous Potato Soup

My mom's famous soup recipe.
In a pan melt a stick of butter on medium and sweat a whole yellow onion to soften, you don't want any color on the onion. Cube 6-8 potatoes and add to pan. Salt and pepper to taste and add water to cover the potatoes, kick up the heat. When potatoes are fork tender add a can of condensed milk. Add the drop dumplings into the boiling soup, while stirring the pot in a circular motion. Dumpling ingredients: 2 cups flour, salt and pepper to your taste and 4 eggs. Do not mix too much as they will get tough, all the flour doesn't have to incorporated as it will work as a thickener, but most of it should be. You just make them all sizes and just drop them off the spoon or with your hand. The dumplings will rise to the top in minutes. Then the soup is done. We usually let it cool just a bit before eating,