Heat oil in a large, deep non-stick frying pan or a large deep saucepan over a medium heat. Add onion and garlic and cook, stirring often, for 3-4 minutes or until the onion is soft and light golden.
Add korma paste and lentils. Cook, stirring, for 1 minute. Stir in tomatoes, water and stock cube. Bring to the boil. Reduce heat and cover with lid. Simmer, covered for 10 minutes.
Stir in cauliflower, eggplant and mushrooms. Cover and simmer for 15 minutes. Stir in beans. Simmer, uncovered for a further 5 minutes, or until vegetables are tender. Remove from heat. Stir in coriander.
Serve with yoghurt and pita bread