In a large mixing bowl, combine ground beef, grated onion, eggs, breadcrumbs, paprika, salt, black pepper, and milk. Mix well with your hands.
Use your hands to form the mixture into small meatballs (approximately 1.5 inches in diameter) and place them on a baking sheet lined with parchment paper.
Bake the meatballs in the preheated oven for 20 minutes.
While the meatballs are baking, make the sauce. In a large saucepan, sauté chopped onion in oil until soft and translucent.
Add flour and tomato paste to the pan and stir well.
Slowly add beef broth to the pan, stirring constantly to prevent lumps.
Bring the sauce to a boil and let it simmer for 5-7 minutes, stirring occasionally, until it thickens.
Season the sauce with salt and pepper to taste.
When the meatballs are done baking, add them to the sauce and simmer for 10-15 minutes, until the meatballs are fully cooked and the sauce has thickened.
If the mixture is too sticky to handle, add a little more breadcrumbs to absorb the moisture.If you are short on time, form the mixture into meatballs instead of the traditional oval-shaped patties.You can also add grated cheese to the mixture for added flavor and moisture.