Step 1

Soak the bread: Pour 1/2 cup of the stock into a small bowl and add the bread. Set aside.

Step 2

Cook the bacon and onions: Set a fine-mesh sieve over a mixing bowl and position it near the stovetop. Heat a large saucepan over medium-high heat and add the bacon; stir and cook until the bacon is lightly browned. Add the onions and cook until they are translucent and the bacon is golden, about 4 minutes. With a slotted spoon, scoop the bacon and onions into the fine-mesh sieve to drain and cool. Turn the heat off under the pan and set aside.

Step 3

Prepare the meatball mixture: In another large mixing bowl, combine the ground chuck, pork, egg yolks, garlic, 1 teaspoon salt, 1/2 teaspoon pepper, allspice, nutmeg, and ginger. Add the bread, which has by now swelled, softened, and become mushy. When the bacon and onions have cooled, add them to the mixture. With your clean hands, mix well to incorporate.

Step 4

Roll the meatballs: Preheat the oven to 200°F. Line a rimmed baking sheet with parchment paper. Using a scoop or spoon, scoop about 1 1/2 tablespoons (about 1 ounce) of the meat into your your hands, roll into a ball, and place on the baking sheet. Repeat with the remaining meat mixture. There should be about 60 meatballs.

Step 5

Fry the meatballs: Return the saucepan to the heat and set it to medium-high. Add 1 tablespoon butter and 1 tablespoon oil and let the butter melt, swirling the pan to coat it. Working in batches, add meatballs, arranging them in a single layer, and sauté until golden-brown on all sides, 7 to 10 minutes. Using a slotted spoon, transfer the meatballs to an ovenproof dish. Tent lightly with foil and place in the oven to keep warm. Add about 1/4 cup of the stock into the pan, scraping up any browned bits, and pour the stock and pan scrapings back to the container holding the rest of the stock. Add 1 tablespoon each of oil and butter to the (more-or-less) clean pan and let it melt. Repeat the process with the remaining meatballs, working in batches as necessary.

Step 6

Prepare the gravy: Once all of the meatballs are cooked, add the remaining 2 tablespoons butter to the pan and heat until it melts. Add the flour and stir, scraping up any small bits, and cook for about 1 minute. Switch to a whisk, and begin to stir. While whisking, gradually add the remaining stock, until well-combined. Remove from the heat, and whisk in the sour cream.

Step 7

Serve the meatballs: Remove the meatballs from the oven, pour the gravy over them, and serve with lingonberry preserves or cranberry sauce if desired.