Huevos Rancheros

Method

1. Set a dry comal or heavy frying pan over medium-high heat. Lay in 2 plum tomatoes and 1 serrano chilli and roast for 8 minutes, turning often, until the skins are blistered and blackened in patches and the tomatoes are soft and collapsing.
2. Tip the charred tomatoes and chilli into a blender with 2 tbsp finely chopped white onion, 1 peeled garlic clove and 0.25 tsp fine salt. Blend to a slightly coarse salsa — it should still have texture, not be a smooth purée.
3. Heat 1 tsp of the oil in a small frying pan over medium heat until it shimmers, then pour in the salsa (it will hiss) and fry, stirring now and then, for 8 minutes until it has darkened, thickened enough to coat a spoon and tastes sweet rather than raw. Taste and adjust the salt, then keep it warm over the lowest heat.