Heat half the oil in a medium saucepan and add the onion. Fry for a minute or two, then add the tomato and a good pinch of salt. Bring to a simmer and cook until the tomatoes have started to break down – about 10 minutes. Remove from the heat and stir in the guajillo sauce. Transfer to a food processor or liquidiser and puree until smooth. Heat the remaining oil in a saucepan over a medium heat and fry the noodles, stirring continuously for a couple of minutes or until they start to colour. Add the sauce and simmer for 15 minutes, adding a little chicken stock if it seems too dry. We suggest serving this with some panela cheese (or Iranian peynir or feta) and a few slices of avocado.
