01 - 
                Warm half the olive oil in a deep skillet over medium heat. Toss in your diced onion and garlic. Cook them until soft for about 5 minutes, then put aside to cool down.
              
              
              
                02 - 
                Take a big bowl and mix the crumbs, Parmesan, beaten egg, milk, the cooled onion mix, salt, oregano, allspice, nutmeg, and pepper. Add meat and mix lightly with your hands.
              
              
              
                03 - 
                Make 1 ½-inch balls and set them on a plate. Cool them in the fridge for 15 minutes or leave overnight if you want. Just cover them if keeping overnight.
              
              
              
                04 - 
                In a big measuring cup, stir together beef broth, chicken bouillon, Worcestershire sauce, Dijon mustard, and parsley. Put it aside for now.
              
              
              
                05 - 
                Pour the rest of the olive oil in a big pan over medium-high heat. Brown your meatballs in small batches, leaving room to turn them easily. Each side needs about 1 minute, then take them out.
              
              
              
                06 - 
                Melt butter in the same pan over medium heat. Scrape the pan bottom with a silicone tool. Sprinkle in flour and stir constantly for 2 minutes.
              
              
              
                07 - 
                Slowly pour in your broth mix while stirring. Let it boil, then turn down to simmer. Mix ¼ cup of this sauce with sour cream in a small bowl, then stir it back into the pan on low heat.
              
              
              
                08 - 
                Put meatballs back in the pan along with any juices. Drizzle sauce over them, partly cover, and cook gently for 10-15 minutes until they're done inside.
              
              
              
                09 - 
                Sprinkle with fresh parsley and serve them over mashed potatoes or egg noodles.