Prepare the Meatballs: In a large bowl, combine ground beef, ground pork, onion, garlic, milk, egg, panko breadcrumbs, salt, and pepper. Gently mix until just combined. Roll into 1 1/2-inch balls (about 2 tablespoons each).
Brown the Meatballs: Heat olive oil in a skillet over medium heat. Add half the meatballs and brown on all sides (about 8 minutes). Repeat with the second batch, setting all browned meatballs aside.
Make the Gravy: In the same skillet, melt butter over medium heat. Whisk in flour and cook until golden brown (1–2 minutes). Gradually whisk in beef stock and cream. Bring to a simmer, then whisk in Worcestershire sauce, Dijon mustard, and dill pickle juice. Season with salt to taste.
Simmer the Meatballs: Reduce heat to medium and return the meatballs to the skillet. Simmer for 5–7 minutes, stirring occasionally, until the meatballs are cooked through and the sauce thickens.
Serve: Enjoy warm over mashed potatoes, noodles, or with a side of lingonberry jam for a traditional Swedish twist.