If you buy your meat at a supermarket, just follow the instructions in the recipe and pulse it in a food processor until smooth and almost paste-like.
[...] after adding all the spices, knead the meat on the counter (yes, like dough) until it's smooth and sticky.
Different cultures call for different spices, so I chose the mix that most appealed to me: cumin, paprika, allspice, pepper and fresh parsley.
Onions and garlic are universal, but they're always added in raw form.
1 tablespoon extra-virgin olive oil, plus extra for brushing on the meat
In a medium skillet, cook the onion in the oil over medium low heat, stirring occasionally, until it is golden brown, about 8 to 10 minutes.
In a food processor, combine the cooled onion mixture, the beef, lamb, paprika, cumin, salt, allspice and pepper and pulse the mixture until it forms a paste and is tacky to the touch.
Divide the meat mixture into 8 equal portions and shape each portion into a log around a skewer, about 5-inches long and 1-inch wide.
In a medium bowl whisk together the tahini, yogurt, lemon juice, garlic and 3 tablespoons water, adding additional water if necessary to achieve a pourable consistency.
Top the meat with one fourth of the sauce and some shredded lettuce and serve with the hot sauce on the side.
Nutrition information per serving: 482 calories; 255 calories from fat; 28 g fat (7 g saturated fat; 1 g trans fat); 74 mg cholesterol; 722 mg sodium; 25 g carbohydrate; 3 g fiber; 3 g sugar; 32 g protein.