In a large pan, heat the oil and cook the onion gently for 4 minutes. Add the garlic and cook for 1 minute, then the potatoes, sweet potatoes and carrots and cook for 2 minutes. Stir in the curry powder.
Add 200ml (7fl oz) water and simmer for 15 minutes with a lid on. Stir well adding the spinach, tomatoes and baby corn and replace the lid. Cook for 5 minutes. Stir in the yogurt and lower the heat for a few minutes. Sprinkle with coriander to serve.
Crush the coriander, cumin and cardamom seeds. Place the rice in a pan, add water, cinnamon, lemon peel and the crushed seeds, bring to the boil and simmer for 8 minutes. Drain and serve with the curry.