Step 1 Roughly chop 1/2 cup mint leaves and place into a food processor with lamb, onion, seasoning, orange zest, 2 tablespoons orange juice, breadcrumbs and egg. Blend until well-combined and a mince forms. Roll tablespoons of mixture into balls and place onto a large plate.
Step 2 Put yoghurt into a small processor. Roughly chop remaining mint and add to yoghurt. Blend until a smooth, pale green sauce forms. Transfer into a serving bowl. Cover and refrigerate.
Step 3 Pour stock and one cup water into a saucepan and place over medium heat. Add quinoa and bring to the boil. Reduce heat and cook for 20 minutes, or until liquid is absorbed and quinoa is tender. Remove from heat, stir and cover. Stand for 5 minutes. Fluff with a fork and add remaining orange juice. Stir until combined, then set aside.
Step 4 Place a non-stick frying pan over medium low heat and spray with oil. Add meatballs and cook, shaking pan often, for 10 minutes, or until meatballs are cooked through.
Step 5 Meanwhile, steam or boil carrots until tender-crisp. Spoon quinoa onto serving plates and top with meatballs. Spoon mint yoghurt onto meatballs. Serve with baby carrots and rocket.