Combine the spices in a small bowl (turmeric, onion powder, ground coriander, cumin, Spanish paprika, sweet paprika, cayenne pepper, all spice, dried oregano, ground cardamom).
Place the chicken thighs in a large bowl and add the tomato paste, lemon juice, olive oil, and a heavy pinch of kosher salt (approx. ½ tsp). Mix thoroughly and marinate—preferably overnight, or at least1 hour.
Preheat the oven to 375°F
Layer the chicken on the at-home vertical spit, rotating each thigh to ensure an even stack. Place the tomato on top and scatter the roughly chopped onions at the bottom.
Place the spit in the oven. Depending on the thickness of the thighs, roasting can take anywhere from 1 hour to 1 hour and 20 minutes. Every 20 minutes baste the chicken with the juices. Roast until fully cooked through.
When done, remove from the oven and shave the meat off. Enjoy in a sandwich, a bowl, or right off the spit.