2 (10.5 ounce) cans condensed cream of chicken soup
2 cups heavy whipping cream
cut into 1-inch cubes
Mix flour, eggs, milk, and salt together in a bowl, beating dough until it holds together. Turn dough out onto a well-floured work surface, knead a few times until no longer sticky, and roll dough out about 1/2 inch thick. Cut the dough into 1- to 1 1/2-inch squares.
Bring a large pot of lightly salted water to a boil and gently drop the dumplings into the boiling water a few at a time, stirring to keep them from sticking. Boil until all dumplings have risen to the top, 8 to 10 minutes. Remove from water with a slotted spoon and transfer to a bowl.
Bring chicken broth to a boil in a large soup pot and whisk in cream of chicken soup and cream until soup is smoothly combined. Stir in potatoes, onion, and dumplings, reduce heat to medium-low, and simmer until dumplings and potatoes are tender and the soup is thickened, 25 to 40 minutes.