Sift the gram flour and cornmeal into a bowl and make a well in the centre. Gradually whisk in 400ml water, to make a smooth thick batter. Set aside.

For the cashew cream, put the cashews in a bowl with 100ml boiling water, the lime juice and half the coriander, then blitz with a hand blender until smooth and creamy. Add 1 tbsp more water if needed, to loosen.

For the mushrooms, heat the oil in a large non-stick pan. Stir in the mushrooms and garlic, then put the lid on the pan for about 5 mins so they start to steam in their own juices. Stir with the lid off the pan for a few mins more until softened, stirring occasionally. Add the cumin seeds, chilli powder and ground coriander, then stir in the pinto beans and tomato purée. Cook for 2-3 mins, adding a splash of the reserved bean liquid to loosen. Add the tomatoes and cook for a few minutes until softened, but not completely broken down. Stir in the remaining coriander and set aside, covered.

Heat the oil for the tacos in a 20cm non-stick frying pan. For one taco, add 4 tbsp of the batter and swirl to cover the base. Cook for 1-2 mins on each side, until browning in spots. Make another three tacos in the same way, keeping the cooked ones warm in a low oven. Cover and chill the rest of the batter for another day, or cook all eight tacos, if you prefer. The batter will keep chilled for up to three days.

Fill four hot tacos with half the shredded lettuce, half the cashew cream and half the mushrooms. Cover and chill the rest for another day. Will keep chilled for up to three days. Reheat the mushrooms in the microwave and make four wraps using the remaining batter, or heat the cooked ones in a dry frying pan over a medium heat until warmed through.