Mixed bean burgers with smoky chipotle crust

Put the onion in the large bowl of a food processor and pulse until finely chopped. Heat ½ tbsp oil in a large nonstick frying pan and add the onion and cumin. Fry, stirring regularly, for 5 minutes, then tip into a mixing bowl.

Put most of the coriander in the bowl of the food processor (reserving some of the leaves to garnish) with the beans. Whizz until a thick paste has formed, then add to the bowl with the onions. Season and stir to combine, then divide the mixture in ½, form into 2 patties and roll in the chipotle crust to coat.

Wipe out the pan used to fry the onions and heat the remaining 1½ tbsp oil over a medium heat. Fry the burgers for 4 minutes on one side, reducing the heat if needed, then carefully flip them over. Top each one with a cheese slice, cover with a lid and fry for 4 minutes more, or until the cheese has melted. Spread each bun with 1 tbsp salsa, then top with a burger, another 1 tbsp salsa, avocado, the remaining coriander and the bun lid.