Preheat the oven to 400 F (200 C).
Mix all the tahini ingredients in a bowl and set aside.
Mix the beef, vegetables, olive oil and spices and form a big patty.
Place the patty in a round baking pan, leaving some space for the chickpeas between the pan wall and the beef. Pour the tahini sauce on top and cover everything.
Put parchment paper on top, then a layer of tin foil and bake for 20 minutes.
Remove the cover and bake until the top starts to brown, about 5-10 minutes. Remove from the oven and serve with a fresh and fluffy pita.