For the marinade: tip all of the marinade ingredients, except for the cracked black peppercorns, into a mini food processor or pestle and mortar and blend or crush to form a smooth paste. Stir in the crushed peppercorns.
For the beef: rub the salt, lemon juice and turmeric all over the outside of the beef. Next, rub half of the marinade mixture on the inside of the beef then roll up and tie securely with string. Rub the remaining marinade over the outside of the beef, place in a large dish and cover.
Cover the beef, transfer to the fridge and marinate overnight or for up to 3 days.
For the mendu wada: wash the lentils in several changes of cold water until the water runs clear. Tip the washed lentils into a large bowl and pour in enough cold water to cover the lentils by 2 inches. Cover and set aside to soak overnight, for 10-15 hours, or until soft.
The following day, drain the lentils and tip them into a food processor. Blend to a purée, gradually adding enough cold water until the mixture is thick and creamy.
Cover and set aside to ferment for 2-4 hours (this will give a lighter texture when frying).
About 20 minutes before you’re ready to cook the beef, preheat the oven to 200C/Gas 6.
Transfer the marinated beef to a large ovenproof dish or roasting tin and place on the top shelf of the oven to brown for 10 minutes. After 10 minutes, reduce the heat to 170C/Gas 3 and cook for about 45 minutes, or until cooked to your liking.
While the beef is cooking, heat the tablespoon of sunflower oil in a frying pan over a medium heat and fry the onions for 5-6 minutes until soft and golden-brown. Stir in the chopped tomatoes and simmer for 4-5 minutes then set the pan to one side.
. To finish the mendu wada, stir the black peppercorns, chillies, fenugreek seeds and ginger into the lentils.
. Heat the oil for deep frying in a deep fat fryer. Test when the oil is ready by adding a small drop of the lentil batter, it should bob on the surface of the oil and sizzle.
. Roll the batter into golf ball-sized balls, or shape into doughnut shaped patties, and fry in the hot oil until crisp and golden. Remove from the oil using a slotted spoon and drain on kitchen paper. Keep warm until ready to serve.
. To finish the beef, transfer the beef to a large board and leave to rest for 15 minutes. Skim the fat off the top of the pan juices and pour the juices into the pan with the fried onions and tomatoes. Bring to a gentle simmer, heat through then stir in the coriander and mint.
. To serve, carve the beef into slices. Pour the onion and tomato sauce over the beef and serve the mendu wada alongside. Serve with cumin roasted parsnips and carrots, if you like
