Grind white bread into crumbs until you have 3 tbsp (or use 3 tbsp pre-made bread crumbs).
Press 2 cloves garlic. In a bowl, combine the minced pork and beef, 1 egg, 3 tbsp bread crumbs, half the pressed garlic, salt to taste, ground black pepper to taste, and 0.5 teaspoon dried oregano. Mix thoroughly until fully combined.
Form the mixture into small meatballs.
Heat vegetable oil in a large frying pan over medium-high heat. Fry meatballs on all sides until golden brown, about 8-10 minutes.
If excess fat remains in the pan, drain it. Add the 400 g canned tomatoes in their own juice to the pan. Stir in the remaining pressed garlic and 0.5 teaspoon dried oregano. Season with salt and pepper to taste. Bring to a boil over medium-high heat, stirring occasionally, about 2-3 minutes.
Return meatballs to the hot tomato sauce. Reduce heat to medium-low, cover with a lid, and simmer for 20-30 minutes until meatballs reach an internal temperature of 63°C (145°F).
Serve with mashed potatoes, pasta, or porridge. Top with chopped green onions if desired.