For the Mexican bean mixture:
1 tbsp oil
1 red capsicum (pepper), diced
125 g green beans, sliced (~ 1 cup when sliced)
5 medium mushrooms, diced
400 g tin black beans, drained (240g, or ~ 1 1/4 cups, when drained)
435 g tin refried beans (~ 1 1/3 cups)
1 tsp smoked paprika
1 tsp hot chill powder
1/2 tsp ground cumin
For the cheesy sauce:
2 tbsp butter
2 tbsp plain flour
400 ml milk (~ 1 1/2 cup) warmed – an important step if you don’t want a lumpy sauce
100 g cheddar cheese, grated (~ 1 cup when grated)
12 no-boil lasagne sheets
Extra cheese for topping (optional)
Fresh coriander (cilantro), to garnish
Heat the oil in a large frying pan, and add the chopped vegetables. Cook for a few minutes over medium heat, until fairly soft. Add the black beans, refried beans, and spices, and season to taste. Depending on the kind of refried beans you use, you may want to add additional spices or seasonings at this point (the beans I used were already fairly spicy). Mix thoroughly – you may need to add a dash of water if the mixture seems too thick. You could also add a tin of tomatoes if you prefer a saucier lasagne.
Melt the butter in a small saucepan, and add the flour. Mix well, and cook over low heat for 1-2 minutes. Add the warmed milk a little at a time, stirring the mixture until smooth each time before adding more. When you have added all of the milk and you have a smooth sauce, add the grated cheese and plenty of salt and pepper. Cook for another minute or two, to melt the cheese.
To assemble the lasagne, start by adding about 1tbsp of cheese sauce to the base of your baking dish, and spread it around – this helps to prevent the lasagne from sticking. From this point onwards, it doesn’t really matter what order you layer up your sauce, beans, and pasta. I layered up pasta, then beans, then sauce, until all the ingredients were used. I finished the lasagne with the last of the cheese sauce, and sprinkled some extra grated parmesan cheese on top.
Cover the lasagne loosely with foil, and bake for around 1 hour at 190°C (Gas Mark 5 / 375°F). When the lasagne sheets are nearly soft (check them with a sharp knife), remove the foil, and bake for a further 20 minutes or so, to crisp up the top. Allow to stand for 5 minutes before cutting, and serve topped with fresh coriander (cilantro) if desired.