Combine ground beef, pork sausage, bread crumbs, minced onions, salt, pepper, allspice, beaten egg, and milk in a bowl.

Mix all ingredients thoroughly.

Form the mixture into approximately 24 meatballs.

Heat a skillet over medium-high heat.

Brown the meatballs on all sides in the hot skillet.

While meatballs are browning, dissolve 3 beef bouillon cubes in 2 cups of boiling water to create beef broth.

Pour the beef broth over the browned meatballs in the skillet.

Reduce heat to low, cover, and simmer for 30 minutes.

Remove the meatballs from the pan, leaving the beef broth behind.

In a separate bowl or measuring cup, whisk together 2 tablespoons of flour and 1 cup of milk until smooth.

Slowly pour the flour-milk mixture into the beef broth in the skillet, stirring constantly to prevent lumps.

Cook the gravy over medium heat, stirring continuously, until it thickens.

Return the meatballs to the pan, coating them evenly with the gravy.

Serve the Swedish meatballs hot.