Mint yogurt sauce - Set aside ½ cup yogurt. Place all other ingredients in a jug that fits the head of a stick blender. Blitz until it turns green - it will be runny. Stir in reserved yogurt (this thickens it again). Refrigerate until required.
Meatballs - Place all Meatball ingredients in a bowl. Mix well with your hands. Measure out 1 heaped tablespoon, then roll into balls. Repeat with remaining mixture - should have 20 - 24 meatballs.
Cook - Heat oil in a large non stick pan over medium heat. Add half the meatballs and cook, turning to brown all over, for 8 minutes, or until cooked through. Transfer to plate. (Oven option - Note 4)
Serving - Cut pita pockets in half, warm for 10 seconds in the microwave, then pry it open. Stuff with lettuce, tomato, onion, then meatballs (I do 2 per half pocket). Drizzle with Mint Yogurt Sauce and fresh coriander.
