How to Make It
Season the peppers and zucchini inside and out with salt and pepper and arrange them snugly, hollow side up, in a medium saucepan.
In a medium bowl, combine the beef, onion, tomato, rice, parsley, olive oil, thyme, 2 teaspoons of salt and 1 teaspoon of pepper and mix well. Spoon the filling into the peppers and zucchini.
In a small bowl, whisk the tomato paste with 1 cup of water; pour the mixture around the vegetables in the saucepan and bring to a simmer. Cover and cook over moderately low heat until the vegetables are tender and the filling is cooked through, about 25 minutes.
In another small bowl, stir the yogurt with the garlic. Transfer the stuffed vegetables to a platter and drizzle with some of the sauce from the pan. Spoon the yogurt on top, sprinkle with Aleppo pepper and serve.