Place the chicken in a shallow dish. Pour over buttermilk.
Turn to coat with buttermilk. Cover with plastic wrap and place in the fridge for 2 hours to rest.
Pre heat oven to 200 C. Line 2 baking trays with baking paper.
Combine the flour, sesame seeds, paprika, cumin, coriander, oregano, fennel, garlic salt, onion salt and pepper in a large bowl.
Skake off excess buttermilk from 1 piece of chicken and toss in flour mixture. Turn to coat.
Place on lined tray. Repeat with remaining chicken and flour mixture.
Spray chicken with oil. Bake, turning occasionally and swapping trays half way through cooking, for 40 to 45 minutes or until golden brown and cooked through.