For meatballs:

• 500 gr. minced meat
• 1 egg
• ½ cup breadcrumbs
• 1 clove of garlic
• 2 tablespoons grated onion
• 1 tablespoon of finely chopped parsley
• 1 teaspoon of sweet chili powder
• Salt
• Black Pepper
• 2 tablespoons of flour

For the soup:

• 2-3 tablespoons of olive oil
• 1 onion, chopped
• 3 stalks of celery, chopped
• 3 carrots, peeled and diced
• 3-4 potatoes, diced
• Salt, black pepper
• 2 liters of water 

For the soup sauce:

• 2 egg yolks
• 1 tablespoon of lemon juice
• 150 g yogurt