Start by boiling a large pot of water. Carefully remove the core from the cabbage and once the water is boiling, submerge the whole cabbage head. Cook for about 5-7 minutes until the outer leaves become tender and pliable, then gently peel them off. Set aside the leaves and reserve the boiling water for later.

In a large skillet, heat a splash of olive oil over medium heat. Sauté the minced red onion and leek for about 4-5 minutes until they soften and turn translucent, then add the spring onion, cooking for another 2 minutes. Transfer the mixture to a bowl and combine it with the pre-cooked rice and ground meat, seasoning generously with salt, pepper, dill, and parsley.

Take a cabbage leaf, placing it flat on a clean surface. Spoon about two tablespoons of the meat mixture near the base of the leaf. Fold the sides over the filling and roll tightly towards the top to create a sealed roll. Place each roll seam-side down in a large pot, ensuring they fit snugly but don't overcrowd.

Layer the bottom of the pot with some of the reserved cabbage leaves and the carrot sticks. Place the cabbage rolls in a single layer on top and sprinkle bay leaves and celery among them. Drizzle with olive oil, season with salt and pepper, and pour in enough of the reserved cabbage water to cover the rolls. Bring to a gentle simmer, cover, and cook for about 1 hour, until the rolls are tender and the filling is cooked through.

While the cabbage rolls are cooking, create the Avgolemono sauce. In a medium bowl, whisk together the room temperature eggs and freshly squeezed lemon juice. Gradually add two ladles of hot broth from the pot into the egg mixture, whisking continuously to avoid curdling. Once combined, pour the egg-lemon mixture back into the pot and stir to incorporate, cooking on low heat for an additional 5 minutes until the sauce thickens slightly.

Once the Greek stuffed cabbage rolls are fully cooked, gently pour the Avgolemono sauce over them. Allow the rolls to simmer for another 5-10 minutes, giving the flavors a chance to meld beautifully. The sauce will coat the rolls, enriching each bite with its creamy, tangy goodness.