Preheat the oven to 425 °F (218 °C) (convection/fan setting, if possible).
Dry chicken thighs with paper towels really well to remove all the excess moisture.
Line a baking sheet with parchment paper.
Place all the dry ingredients in a bowl and mix them together.
Rub the spice mix all over each thigh.
Lay the chicken thighs on the parchment paper, leaving space between the pieces.
Bake for 35-40 minutes. Once the thighs are fully cooked, you can uses their juices to baste each piece.
Notes
Do not use baking soda in place of baking powder - it will not turn out the same.If you have a baking stone, this will work especially well, no parchment paper needed.