I made the Mexican Lasagne from 'Nigella Kitchen'. I followed the ingredients and instructions exactly and unfortunately, I had did not have the results that I expected. The cooked finished lasagne was very watery and my tortillas were just mush (and yes I had drained the black beans and sweetcorn). Please could you explain were I could have gone wrong with this recipe? Should I exclude the 400ml of water from the ingredients?
We are sorry that you experienced this with Nigella's Mexican Lasagne (from Kitchen) as the recipe has been popular with many people. We suspect that the problem lay with the canned tomatoes which, in our experience, can vary quite a lot in their consistency.
We would suggest looking for cans of tomatoes that are labelled as having a "rich tomato sauce" as these tend to have a thicker sauce around them. Other cans can contain tomato juice which varies from thin to quite watery. If you open the can of tomatoes and the juice looks quite thin then reduce or omit the water, or cook the sauce for longer so that it thickens sufficiently. It should be thick enough to coat the back of a spoon but not as thick as the sauce you would use for topping a pizza.
The cooking time for the sauce can also vary, depending on the size of pan used. If a smaller, deeper pan is used then the sauce will not have a particularly big surface area and will take longer to reduce and thicken. A wide pan, such as a wok or deep-sided frying pan, will help the sauce to thicken more quickly.