Add the cubed bread and milk to a large bowl. Let the bread soak for 5 minutes.
3 slices white bread, ½ cup milk
Add the ground beef, ground pork, onion, egg, salt, pepper, allspice, nutmeg, and garlic powder to the bowl of bread and milk. Mix well with your hands until combined.
1 pound ground beef, 1 pound ground pork, 1 egg, 1 teaspoon salt, ½ teaspoon black pepper, ¼ teaspoon ground allspice, ¼ teaspoon ground nutmeg, ⅛ teaspoon garlic powder, ½ large onion
Form about 30-35 small meatballs (each about 1" in diameter) and set aside on a baking sheet or plate.
Bake at 425°F for 10 minutes until lightly browned or heat a drizzle of olive oil over medium-high heat in a large skillet and sear the meatballs for about 4-5 minutes, rotating to brown on all sides. Set aside or freeze for later use.
In a 3-4 quart slow cooker, whisk together the broth, evaporated milk, cornstarch, Worcestershire sauce, salt, and pepper. Add the browned meatballs.
2½ cups beef broth, 1 cup evaporated milk, 2 Tablespoons Worcestershire sauce, 1 teaspoon coarse kosher salt, ½ teaspoon black pepper, ¼ cup cornstarch
Cover the slow cooker with the lid and cook for 3-4 hours on LOW or 2 hours on HIGH until the sauce has thickened and the meatballs have cooked through, stirring partway through.
Serve over pasta, mashed potatoes, or rice.