Start by finely chopping the onion and gathering all your ingredients together on the counter to ensure a smooth cooking process.

In a large mixing bowl, combine the ground beef, ground pork, breadcrumbs, milk, chopped onion, egg, salt, and pepper. Mix lightly until just combined; be careful not to overmix for tenderness.

Using your hands, roll the mixture into 1-inch balls, ensuring each meatball is uniform in size for even cooking.

Heat 2 tablespoons of oil in a skillet over medium heat. Add the meatballs in batches, cooking each batch for about 5 minutes until they are golden brown on all sides.

In the same skillet, carefully deglaze the pan with beef broth and Worcestershire sauce, scraping up the brown bits. Stir in the sour cream till the sauce is creamy and well combined.

Gently add the browned meatballs back into the skillet with the sauce. Allow them to simmer together for 10 minutes on low heat, then serve over fluffy mashed potatoes or buttered noodles.