Heat the slow cooker to low. Heat the oil in a frying pan and cook the onion for 10 mins until soft and transparent. Add the carrots and parsnips and fry for 8-10 mins more until the veg is just golden. Stir in the garlic and spices, and fry for 4-5 mins until fragrant, stirring. Add a splash of water if needed. Tip into the slow cooker and stir through the lentils, stock, bay and seasoning.

Close the lid and cook on low for 5-6 hrs until the vegetables are tender and the sauce has thickened. Check the seasoning and stir in the lemon juice to taste. Serve with bread, rice, or potatoes, if you like.