In a small bowl, combine Panko and milk. Let sit 5 to 10 minutes, stirring once, until fully softened. The mixture should be moist and slightly paste-like.

In a large bowl, combine ground beef, ground pork, hydrated Panko mixture, grated onion, garlic, egg, Dijon, Worcestershire, salt, black pepper, white pepper, allspice, nutmeg, and cardamom.

Mix gently just until combined. Do not overwork.

Roll into 1½ inch meatballs. Place on a tray and chill for 10 to 15 minutes to help them hold their shape while browning.

Heat butter and oil in a large skillet over medium heat. Brown meatballs on all sides until cooked through, about 8 to 10 minutes. Work in batches if needed. Transfer to a plate and reserve pan drippings.

In the same skillet, melt butter over medium heat. Whisk in the flour and cook for 1 to 2 minutes, until lightly golden.

Slowly whisk in beef broth. Simmer until slightly thickened. Stir in heavy cream and continue cooking until smooth and creamy.

Reduce the heat and stir in sour cream, Dijon, and Worcestershire. Season with salt and white pepper to taste.

Return the meatballs to the skillet and simmer gently for 5 minutes, until heated through and coated in the gravy.

If lingonberry jam is unavailable, stir fresh lemon juice into whole berry cranberry sauce.

This simple adjustment provides the same bright, sweet-tart contrast that balances the richness of the cream sauce.

Serve on the side.