Persian Koobideh Beef Kebab Recipe

Name: Persian Koobideh Beef Kebab Recipe
Ingredients: 3 lbs (1.36 kg) ground beef (80/20 for best results); 1 large onion, grated (about 1 cup / 150 g, excess liquid squeezed out); 4 cloves garlic, minced; 1 tablespoon (6 g) ground cumin; 1 tablespoon (6 g) ground coriander; 1 teaspoon (2 g) cinnamon; 1 teaspoon (2 g) smoked paprika; 1 teaspoon (2 g) sumac (optional, adds a tangy, authentic flavor); 2 teaspoons (15 g) salt; 1 teaspoon (2 g) black pepper; ½ teaspoon (1 g) chili flakes (adjust to taste); ¼ cup (10 g) finely chopped parsley; 1 egg (about 50 g); ½ cup (60 g) gluten-free breadcrumbs (for better tenderness & binding)