2 1/2 pounds bone-in ham 4 large Russet potatoes 1 1/2 teaspoon salt 1 1/2 teaspoon baking powder 1 cup oatmeal 2 cups flour, or as needed
Boil ham (covered with water) in a heavy pot for 3 or 4 hours on low heat after it comes to a boil. Heat must be high enough to keep the water boiling. Preheat oven to 275 degrees F to keep ham warm while dumplings cook.
Peel potatoes and cut into 1 inch squares. Put in cold water (so they don't turn brown) until all potatoes are cut up. Drain. Put some potato cubes and water to cover in a blender. Run on chop. Do no chop too finely. As an alternative, shred potatoes with a food processor or grater.
Squeeze water out of potatoes, add salt and baking powder, oatmeal and flour. Mix well. Form into 2 inch balls. Dust with flour.
Remove ham from broth. Put in covered dish and keep warm in the oven. Return broth to full boil. Drop potato balls into boiling broth. Keep broth boiling and shake pan so balls do not stick to the bottom and burn. When broth comes to a rolling boil, turn heat down to simmer 45 minutes to 1 hour, shaking pan often.
Serve kumla with ham, some of the broth, and butter. Great with boiled onions and carrots, too.