Heat 1/2 the oil in a large saucepan over medium heat. Add onion. Cook, stirring, for 3 to 4 minutes or until softened. Add cumin, chilli and garlic. Cook, stirring, for 1 minute or until fragrant. Add tomato paste, stock, about 1/2 the lemon juice and lentils. Cook, stirring occasionally, for 5 minutes or until mixture thickens. Stir in tomato. Cook for 2 minutes.

Stir in tomato. Cook for 2 min. Meanwhile, trim excess fat from beef and discard. Using a meat mallet, pound beef to 5mm thick. Cut into 2 pieces. Rub with remaining oil. Sprinkle with paprika and remaining lemon juice. Season with salt and pepper.

Heat a large frying pan over high heat. Cook beef for 2 to 3 minutes each side for medium or until cooked to your liking. Transfer to a plate. Cover loosely with foil. Set aside for 10 minutes to rest. Slice beef. Add kale to lentil mixture. Stir until just wilted. Top spiced lentils with beef and serve with crusty bread.