1) Put half of the grated carrot in a food processor with the chickpeas, chopped onion, 2 tbsp tahini, cumin and egg. Blend to a thick paste, then scrape into a large bowl.
2) Heat 1 tbsp oil in a large frying pan, add the remaining carrot and cook for 8-10 mins, stirring until the carrot is softened.
3) Add to the paste with the breadcrumbs, lemon zest and sesame seeds. Season to taste, then mix together well with your hands.
4) Divide the mixture into 6, then using wet hands shape into burgers. Cover and chill for 30 mins to allow the burgers to firm up.
5) Mix the yogurt with the remaining tahini and lemon juice, and chill.
6) Heat a non-stick frying pan and brush the burgers with the remaining oil. Cook the burgers for 5 mins on each side, until golden and crisp.
7) Meanwhile toast the buns.
8) When the burgers are ready, spread each bun with some of the yogurt, add the avocado, top with the burger, sliced onion and rocket. Finish with a drizzle of chilli sauce.