In a shallow bowl, mix together 1 tsp. each turmeric, garlic powder, coriander, cardamom, ginger. 1/2 tsp. cayenne. 1/4 tsp. sea salt. Coat 4 large bone-in skin-on chicken thighs with olive oil. Roll them in the spice mix to evenly cover.
Place the thighs in baking pan skin-side up and put sliced onion pieces in between and around the chicken. Bake in a preheated 400 degree oven for 45 minutes or until chicken and onions are crispy. Serve with couscous & chutneys.
For a more tandoor-like taste, add 1 tbs. plain yogurt to the spices and blend thoroughly. Marinate the chicken thighs in the yogurt sauce for a few hours and then bring to room temperature before baking as above.