In a large bowl, combine ground beef, ground pork, egg, almond flour, 60ml heavy cream, grated onion, salt, pepper, allspice, and nutmeg. Mix gently until just combined, being careful not to overwork the meat.

Using wet hands, roll the mixture into 24 meatballs, approximately 3cm in diameter each.

Heat butter and olive oil in a large skillet over medium-high heat. Working in batches to avoid overcrowding, brown the meatballs on all sides for 8-10 minutes, turning occasionally until golden brown and cooked through to an internal temperature of 74°C (165°F). Transfer to a plate and set aside.

Reduce heat to medium and add beef stock to the skillet, scraping up any browned bits from the bottom of the pan with a wooden spoon.

Stir in 240ml heavy cream and Dijon mustard. Bring to a gentle simmer and cook for 5 minutes until slightly reduced.

Sprinkle xanthan gum over the sauce while whisking continuously to prevent lumps. Simmer for 2 more minutes until sauce thickens to coat the back of a spoon.

Stir in chopped fresh dill and season with salt and pepper to taste.

Return meatballs to the skillet and gently coat with the creamy dill sauce. Simmer for 3-4 minutes until meatballs are heated through.

Serve immediately, garnished with fresh dill sprigs. Pairs beautifully with cauliflower mash or steamed spring vegetables.