Add panko breadcrumbs to a bowl with heavy cream, milk, a whole egg, and Dijon mustard. Mix and let sit for 5 minutes.
Add ground beef, ground pork, allspice, salt, and black pepper, then mix until well combined. Form into golf-ball-sized meatballs and chill in the fridge for 1 hour.
Sear the meatballs in a pan with olive oil. Butter baste with herbs until fully cooked, then remove the meatballs from the pan.
In the same pan, reduce the beef stock with heavy cream. Once reduced, add Dijon mustard and whisk to make the gravy.
Warm the meatballs in the gravy before serving.
Boil the potatoes from cold water for about 35 minutes, or until tender. Peel the potatoes while warm, then pass them through a sieve.
Add the potatoes to a pan over low heat and gradually fold in the butter until creamy.
Pour in the milk and season with salt and gently fold.
Cook the lingonberries in a pan over medium heat with sugar and lemon juice until they reach a jam-like consistency. Do not squish the lingonberries so they retain their shape.
In a saucepan over low heat, cook the sugar with white wine vinegar, water, and mustard seeds until the sugar dissolves.
Add the sliced cucumbers and dill, then transfer to a container.
