Heat 2 tbsp olive oil in a large sauté pan set over a medium heat until hot. Add the onion, garlic, dried herbs and a pinch of salt.
Sauté for 5-6 minutes until softened before adding the chickpeas. Cook for a further 2-3 minutes and then tip into a bowl.
Add the breadcrumbs, egg and cornstarch, mashing well until combined. Shape into four patties and chill on a lined baking sheet for 30 minutes.
After chilling, dust the patties in a little extra cornstarch, shaking off the excess.
Heat remaining olive oil in a large sauté pan set over a moderate heat until hot. Pan-fry the patties for 3-4 minutes on both sides, until golden-brown on the outside. Remove from the pan and set aside to cool.
Line four lettuce leaves with a slice of tomato. Sit the patties on top and spread with ketchup.
Top with slices of pepper, red onion, cucumber and more tomato. Serve with the remaining lettuce leaves on top.