• Step 1: In a large bowl, combine the ground beef, ground pork, panko breadcrumbs, milk, eggs, onion, garlic, allspice, nutmeg, salt, and pepper. Mix until just combined, being careful not to overmix.
• Step 2: Using a small cookie scoop or your hands, form the mixture into 1-inch meatballs and place them on a parchment-lined baking sheet.
• Step 3: In a large skillet over medium-high heat, melt the butter. Working in batches, brown the meatballs on all sides, about 2-3 minutes per batch. Transfer the browned meatballs to a plate.
• Step 4: In the same skillet, whisk in the flour and cook for 1 minute, stirring constantly. Gradually whisk in the beef broth, heavy cream, soy sauce, and Dijon mustard. Bring the mixture to a simmer and cook until thickened, about 5 minutes.
• Step 5: Return the meatballs to the skillet and gently toss to coat them in the creamy gravy. Reduce the heat to low and simmer for 10-15 minutes, or until the meatballs are cooked through and the gravy has thickened to your desired consistency.