Guaranteed juicy Turkish sour meatball recipe / sour meatballs / Figen Ararat

Sour meatballs;
Grated 1 onion
3 tablespoons of rice
1 teaspoon salt
1 teaspoon of black pepper
1/2 teaspoon of cumin
3 -4 tablespoons flour
2-3 tablespoons of olive oil
2 carrots
2 potatoes
7 glasses of water (1.5 liters)

for Finishing;
1 egg yolk
Juice of 1/2 lemon
1 teaspoon salt