In a large bowl,mix toogether 2 tbsp pesto, the minced lamb,salt and freshly ground black pepper until well combined. Shape the mixture into 4 equal burgers. Chill for 30 minutes. Preheat a large chargrill /griddle pan and cook the burgers for 7-8 minutes on each side until cooked through. Add the vegetables and the halloumi cheese 2-3 minutes before end of cooking time and cook until charred with lines.