Spiced red lentils with cucumber yoghurt

My friend and colleague, Helen Goh, is a bit of food encyclopaedia. I am always astounded by how much she knows and how effortlessly she accesses her knowledge. After suggesting that I try this dish, which she hadn’t cooked for years, Helen went on to rapidly recite the long list of ingredients and quantities as if she was reading from her notes. She didn’t miss a single item!