In a large pan, heat the olive oil. Once hot, add the onions and cook for around 4 minutes ot until soft.
Meanwhile, dissolve one stock cube in 600 ml of boiling water.
Once the onion is soft, add the garam masala, ground fenugreek, turmeric, cayenne pepper, chillis and smoked paprika. Stir, then add the garlic, mustard seeds and ginger and cook for 2 minutes until fragrant. If the pan is looking a little dry, you may need to add a little more oil.
Add the drained lentils to the pan, together with the stock and tamarind paste. Give it a good stir and bring to a boil.
Add the chopped green beans, tomatoes and sugar and cook for 15 minutes, stirring occasionally. Add the lime juice and fresh coriander and cook for further 5-10 minutes.
Serve with basmati rice or naan and a dollop of coconut cream.