Method

1. Preheat the oven to 200C/180C Fan/Gas 6.

2. Brush both sides of the tortillas with sunflower oil. Cut them in half to make eight semi-circles, then stack them and slice into 2cm/¾in strips.

3. Spread the strips of tortillas in a single layer on a baking sheet and bake for 7 minutes, turning halfway through cooking, until they are light golden brown. Leave to cool and crisp up on the baking sheet.

4. Mix the onion, lime zest and juice and a good pinch of salt together in a bowl and leave for 5 minutes. Stir in the black beans, cherry tomatoes, coriander and chilli. You can add more or less chilli depending on how hot you like it. Check the seasoning.

5. In a second bowl, lightly beat the eggs and season with salt and pepper.

6. Place a wide non-stick pan over a medium heat and add the butter. When melted, add the eggs and gently scramble. When just cooked, remove from the heat and sprinkle over half the tomato mixture, half the cheese and half the tortilla strips. Give the mixture a quick stir, then spoon onto serving plates. Top with the remaining tortilla strips, cheese, sour cream and finally the rest of the tomato mixture.