If you're going to be having the dish with the brown rice, put it on to cook now.
In a dry saucepan, add the mustard seeds, cumin seeds and fennel seeds and cook on high until they start to jump. Take off the heat and place in a bowl.
Add two to three cms / three to four inches of water to the same pot and cook the onion, chilli and garlic for 4-5 minutes. Then add all the remaining spices, fresh ginger and the toasted seeds to the pot and stir with the onions and garlic for two minutes.
Add the chopped potatoes, cauliflower, lentils, coconut milk and half the stock. Stir them all together. Cover the pot and cook for 15 minutes.
How's it doing? Does it need more of the stock you've set aside? If it does add it now and cook for a further 5 minutes. If it doesn't need anymore stock, keep cooking it for another five minutes anyway.
Keep an eye on the pot throughout the whole cooking time to ensure it doesn't catch on. Stir frequently.
Serve with the brown rice and sprinkle with the desiccated coconut and some freshly ground black pepper.