Tip in the tomatoes and black beans, season with a little more salt and pepper, then bring to a gentle simmer. Leave to bubble gently, uncovered, for 15-20 mins, stirring occasionally, until thick. Use the back of a spoon to make four little hollows in the sauce. Crack an egg into each one, season the eggs lightly, then cover the pan with a lid and cook gently for 5-6 mins or until the whites are just set but the yolks are still soft. Take the pan to the table and finish with coriander scattered over the top. Serve with warm tortillas, sliced avocado or guacamole, soured cream or thick yogurt, lime wedges for squeezing over and hot sauce on the side so everyone can build their own plate.
