Begin by carefully coring the Lebanese zucchini, hollowing them halfway down without piercing the bottom. In a large skillet, heat vegetable oil over medium heat and fry the zucchinis for about 5 minutes on each side, or until they turn golden brown. Once done, remove them from the pan and let them drain on paper towels to absorb excess oil.

In the same skillet, add a splash of olive oil and bring it to medium heat. Sauté the diced onions for 3-4 minutes until they turn translucent. Next, stir in the crushed garlic and ground beef, cooking for about 6-8 minutes until the meat is browned and no longer pink. Drain any excess fat, and then it's ready to be seasoned.

Mix in your preferred spices, including seven spices or allspice, along with a pinch of salt and pepper. To add some crunch, fold in the toasted nuts. This flavorful mixture should be stuffed tightly into the hollowed zucchini, ensuring each piece is filled to the brim for a satisfying bite.

In a separate pan, gently sauté some garlic and cilantro in olive oil until golden. In a bowl, whisk together the full-fat yogurt, egg, cornstarch, and a bit of salt. Heat this mixture gently over low heat, stirring continuously until it thickens (about 5-7 minutes)—avoid boiling to keep it creamy. Finally, incorporate the sautéed garlic and cilantro for added depth.

Carefully place the stuffed zucchini into the yogurt sauce, ensuring they are arranged snugly. Allow them to simmer gently uncovered over low heat for 20-30 minutes, or until the zucchini becomes tender. Keep an eye on the sauce to maintain its creamy texture throughout the cooking process.

Once the zucchini is tender and the sauce is velvety, transfer the stuffed zucchinis to a serving dish. Drizzle some additional yogurt sauce on top, sprinkle with toasted nuts for crunch, and serve alongside vermicelli rice for a complete and comforting family meal.