Place the garlic into the mortar and crush into a paste. The skin should come off by itself, which you can then pick out.
Place the chickpeas, 1 tbsp of olive oil, salt and pepper into the mortar and crush into a paste.
Add 2-3 full spoons of greek yogurt, the lemon juice and the tahini and mix in with the pestle as you continue to grind any remaining pieces of chickpeas.
Keep adding olive oil until you reach the desired consistency.