For the chicken, cut the chicken into strips and place in a large bowl. Add 1 tbsp Cajun spice and 1 tbsp olive oil. Mix until the chicken is fully coated.
Bring a large saucepan to a medium high heat and one heated, add the chicken strips. Let the chicken brown on one side before turning. Remove from the heat and set aside.
For the sauce, add 1 tbsp olive oil, sumac, garlic powder, light brown sugar to a small saucepan and cook for 1-2min on a medium high heat but be careful to not burn the spices.
Add the yoghurt, lemon juice and water to the spices and simmer for 5-8mins or until the sauce has reduced by 1/3 and thickened up beautifully. Salt to taste and set aside until you're ready to assemble.