In a blender pulse the chopped onion and potato until it is completely smooth.

In a large bowl mix the beef, potato-onion mixture, 2 teaspoons salt, 1 teaspoon white pepper, nutmeg, mace, matzo meal, 2 tablespoons sunflower oil and 1 cup water. Set aside and allow the flavors to meld.

In a wide heavy-bottomed pot, heat ¼ cup oil over low heat. Place the thinly sliced onion into the pan and cover, allowing to soften until they are soft and golden, about 15 minutes. Add 3 cups water, 1 teaspoon salt, ¾ teaspoon white pepper and turmeric. Bring the mixture to a boil then reduce the heat and allow to simmer, covered for about 30 minutes.

With oiled hands, shape about 30 balls, about 70 grams each. The mixture will be very soft, so handle it lightly.

Place the meatballs into the simmering sauce, cover and cook for approximately 30 minutes. If you don’t have a pot large enough to fit all the balls in one layer, do this step in batches: Place half the meatballs into the simmering sauce and cook for 10 minutes. Remove and place the rest of the meatballs into the pot, cook for 10 minutes. Then return the rest of the partially cooked meatballs (it’s okay if they’re crowded now) to the pot and continue cooking for another 20 minutes.