Soak the crumbs: In a large bowl, combine the Fine Dry Breadcrumbs with the Milk and let sit for 5 minutes until the crumbs absorb the liquid.
Cook the onion: Finely chop the Onion and sauté in 1 tablespoon of Butter over medium heat until soft and translucent; set aside to cool slightly.
Make the meatball mixture: Add the Ground Beef and Ground Pork to the soaked breadcrumb mixture, then stir in the cooled onion, the Egg, 1 teaspoon Salt, 1/2 teaspoon Allspice and 1/4 teaspoon White Pepper. Mix gently until just combined—avoid overworking the meat.
Shape and chill: Using wet hands, form the mixture into small meatballs (about 1 to 1 1/4 inches). Place them on a tray and refrigerate for 15–20 minutes to help them hold their shape.
Brown the meatballs: Melt 2 tablespoons of Butter in a large skillet over medium-high heat. In batches so you don't crowd the pan, brown the meatballs on all sides until golden and nearly cooked through, about 6–8 minutes. Transfer meatballs to a plate and tent with foil.
Make the gravy base: In the same skillet, reduce heat to medium and add an additional tablespoon of Butter. Sprinkle in the All-Purpose Flour and cook, stirring, for 1–2 minutes to make a roux without letting it burn.
Finish the sauce: Gradually whisk in the Beef Stock until smooth, then stir in the Heavy Cream. Bring to a gentle simmer and season with more Salt and a pinch of White Pepper to taste. Return the meatballs to the skillet and simmer gently for 5–8 minutes until the meatballs are cooked through and the sauce has thickened.
Prepare the lingonberry sauce: Meanwhile, in a small saucepan combine the Lingonberries with 3–4 tablespoons of Sugar and 2–3 tablespoons water. Bring to a simmer over medium heat and cook until the berries burst and the sauce thickens, about 5–7 minutes. Taste and add a little more sugar if you prefer it sweeter.
Make mashed potatoes: Peel and cut the Potatoes into even chunks. Place in salted water and boil until very tender, about 15–20 minutes. Drain, then mash with 2 tablespoons Butter, a splash of Milk and salt Salt to taste until smooth and creamy.
Quick-pickled cucumber: Thinly slice the Cucumber. In a jar or bowl combine 1/2 cup Water, 1/4 cup Distilled Vinegar, 1 tablespoon Sugar, 1/2 teaspoon Salt and a pinch of White Pepper. Stir until sugar and salt dissolve, add the cucumber slices and a few sprigs of Fresh Dill. Let sit for at least 10 minutes (longer for stronger flavor).
Serve: Spoon mashed potatoes onto plates, top with several meatballs and generous amounts of the creamy gravy. Add a spoonful of lingonberry sauce and a helping of pickled cucumbers on the side. Garnish with extra Fresh Dill if desired and enjoy warm.
