Blend the vegetables: In a food processor, blend the onions, tomatoes, bell pepper, chili peppers, and parsley to a fine paste. Squeeze out excess water and set the vegetable solids aside.
Mix the filling: In a large bowl, combine 1 pounds ground beef (at least 25% fat) and 2 pounds ground lamb with the vegetable solids, 1 tablespoons fine salt, 2 teaspoons freshly ground black pepper, 2 teaspoons ground cumin, 2 teaspoons ground coriander, 1 teaspoons sweet paprika, 1 teaspoons freshly grated nutmeg, 1 teaspoons chili flakes (optional), and 0.5 teaspoons ground cardamom. Mix well until evenly combined.
Stuff the pitas: With scissors, snip open the top edge of each pita (10 Aish Baladi (Egyptian whole wheat pita bread)) and fill with about 3/4-1 cup of the meat mixture, spreading it evenly inside.
Sear the bread: Brush each stuffed pita with oil and sear on both sides on a hot griddle, grill pan, or stovetop grill until the bread is crusty and golden.
Bake: Bake the hawashi in a preheated oven at 375°F for 20-25 minutes, until the stuffing is cooked through and the juices run clear.
Slice and serve: With a sharp knife, halve each stuffed pita into pieces and serve with tahini sauce, pickles, and Salata Baladi (Egyptian salad).