Combine beef, pork, breadcrumbs, 30 ml Worcestershire, egg, 1 g each allspice and nutmeg, 3 g salt and 1 g pepper. Mix just until combined. Shape into evenly sized meatballs about 1 inch across.

Heat olive oil in a large skillet over medium heat. Brown the meatballs in batches, turning carefully, and cook until their centers reach 160°F (71°C). Transfer to a clean plate. Avoid crowding the skillet.

Add butter to the skillet. Once melted, whisk in flour and the remaining 0.5 g each allspice and nutmeg. Cook 1–2 minutes, stirring. Gradually whisk in the beef stock, then the remaining 30 ml Worcestershire, 1.5 g salt and 0.5 g pepper.

Simmer gently for 3–5 minutes, whisking, until the gravy thickens. Reduce heat to low and stir in sour cream until smooth; avoid a vigorous boil.

Return the meatballs and their juices. Warm gently for about 5 minutes, coating them with gravy. Divide into six portions. Noodles, mashed potatoes and preserves are optional accompaniments, excluded from the estimates.