Lightly roast sesame seeds in a small pan until they turn golden.
Combine them with freshly chopped thyme. Add half a teaspoon of sea salt and mix together.
Sprinkle the za'tar on both sides of the chicken thighs.
Heat olive oil in a non stick plan and sear the chicken for two minutes on both sides. Transfer the chicken to an oven preheated to 170C and cook for a further 20 minutes.
While the chicken is cooking make the tahini sauce. Simply mix 3 tablespoons of tahini with the juice of 1 lemon, add 2 cloves of crushed garlic and combine. Add water, a little bit at a time, until the sauce has taken on a creamy consistency. Season with cracked pepper.
Toss spinach in a pan for a few minutes until wilted.
Serve the spinach on a plate with a little tahini sauce over it and add the chicken over the top. Serve with a little bit of extra sauce on the side.