Mix the cumin, chilli powder and oregano together with 1 teaspoon sea salt. Sprinkle evenly over both sides of the steaks. Set aside.
To make the burnt corn salsa, cut the corn kernels from the cob. Add a few sprays of oil to a frying pan and place over a high heat. Add the corn kernels and cook for 4 minutes or until beginning to brown. Add the red onion and jalapeño pepper, cook for 2 minutes and take off the heat. Tip into a bowl and add the cherry tomatoes, coriander and lime juice. Season with salt and pepper.
To make the avocado cream, mash the avocado with the soured cream in a small bowl. Season with salt and pepper and stir in the lime juice.
Heat a large frying pan over a high heat and add a few sprays of sunflower oil. Add the steaks to the pan and cook for 3–4 minutes on each side, until cooked to your liking. Remove from the pan and leave to rest.
Heat two large frying pans over a high heat. Add a tortilla to each pan and heat for 30 secondson each side. Remove and repeat with the remaining tortillas.
Thickly slice the steaks and pile onto the warmed tortillas, top with the salsa and avocado cream and serve.