Trim the root and stem ends from all 6 yellow onions, then make one lengthwise cut through each onion to the center.

Place the onions in a pot of boiling water and cook for 10 minutes, until the layers soften but still hold their shape.

Remove the softened onions and let them cool until safe to handle.

Separate the cooled onions into individual layers, reserving the small inner pieces for the cooking pot.

Combine the ground beef, uncooked rice, parsley, garlic, allspice, cinnamon, black pepper, and 1 teaspoon salt in a mixing bowl.

Mix the filling thoroughly until the rice, seasonings, and beef are evenly distributed.

Place about 2 tablespoons of filling at one end of each large onion layer.

Roll each onion layer tightly around the filling and place it seam-side down in a wide pot.

Arrange the stuffed onions snugly in the pot over the reserved small onion pieces.

Whisk the beef broth, tomato paste, lemon juice, olive oil, and remaining 1/2 teaspoon salt until the tomato paste dissolves.

Pour the broth mixture around the stuffed onions until they are nearly covered.

Bring the liquid to a gentle boil over medium heat.

Cover the pot and simmer over low heat for 40 minutes, until the rice is tender and the beef is fully cooked.

Rest the stuffed onions for 10 minutes, then lift them carefully onto serving plates with a slotted spoon.