Heat the oil in a frying pan, add the onion and fry for 10 mins or until softened. Add the chilli and ground coriander and cook for 1 min more. Stir through the sweetcorn, spring onions and lime zest. Season to taste.

Pile the mixture on 1 tortilla, then top with the cheddar, mozzarella and the second tortilla. Heat a frying pan over a high heat. When hot, add the quesadilla, cook for 2 mins on one side, then turn it over and cook for 1-2 mins more, or until the cheese is melted. Cut into four and serve with some chilli sauce, if you like.