Bring the 800ml of water to the boil in a saucepan. Once it's simmering add the polenta and whisk furiously for one to two minutes until the polenta swells and it soaks up all the liquid. Whisking will stop it from getting lumpy.
Next heat the oil until hot, add the asafoetida and the cumin seeds.
Now add the tomato passata, and some water to loosen the mixture. Add the cooked vegetables with the fenugreek leaves, the red onion and some salt. Allow this mixture to cook for a few minute or until the vegetables have warmed through.
Remove from the heat and stir in the lemon juice.
Finish the polenta by adding the ghee and stirring well. Loosen with a little warm water to get a smooth consistency.
Serve by spooning polenta into the dish and topping with the vegetable mixture.
Garnish with the ginger, chillies and coriander. Serve with a spoon of the spicy tomato relish on top.