Remove the seeds from the cardamom pods. Toast the cardamom seeds, black peppercorns, allspice, cumin, and coriander in a dry skillet over medium heat for about 1 minute, just until fragrant. Allow the spices to cool, then grind them together with the paprika, garlic powder, onion powder, oregano, sumac, turmeric, Aleppo pepper, and cinnamon until finely ground. Store any extra spice blend in an airtight jar.

Blend the onion until completely smooth, then strain it through a fine sieve to extract the juice, pressing firmly with the back of a spoon. Discard the pulp.

In a large bowl, whisk together the onion juice, yogurt, vinegar, lime juice, olive oil, garlic, shawarma spice blend, and salt. Add the sliced beef and toss until every piece is well coated. Cover and refrigerate for at least 3 hours, or overnight for even deeper flavor.

Whisk together the tahini, yogurt, and lime juice. Season with salt and pepper, then gradually whisk in warm water until the sauce is creamy enough to drizzle but still thick enough to spread.

Remove the beef from the refrigerator about 20 minutes before cooking.

Heat the lamb fat in a large cast-iron skillet over medium-high heat. Working in batches, cook the beef without overcrowding the pan, allowing it to brown well before stirring. Continue cooking until the meat develops caramelized edges and is just cooked through.

Return all the beef to the skillet. Add the diced tomato and red onion and cook for another 2 minutes, just until they soften slightly while still retaining their texture. Stir in the chopped parsley and taste for seasoning.

For the distinctive aroma of traditional street-side shawarma, place a small heatproof bowl in the center of the skillet. Heat a charcoal briquette until glowing, transfer it to the bowl, and drizzle it with the oil. Immediately cover the skillet tightly and let the smoke infuse the meat for 10 to 15 minutes before serving.