Place the beans in a large saucepan with the cold water and bring the water to boiling point before turning it down to simmer. It will take about 30 minutes until the beans are softened. So meanwhile you can prepare the rest of the ingredients.
Spray the bottom of a medium sized saucepan about 5 times with the low fat cooking spray. Heat the saucepan and once the oil begins to bubble a little turn the heat down.
Add the diced onion, stirring until softened. Then add the ginger and garlic paste and stir for a couple of minutes. Add the chilli powder, turmeric and passata and keep stirring everything together. Move this mixture aside if the mung beans are not softened yet.
Once the mung beans are softened and all the water has been absorbed, add in the onion mixture and stir together well over a very low heat for about a minute.
Add the ground cumin, garam masala, asafoetida, fenugreek leaves and salt and chopped tomato. Combine these ingredients well for a couple of minutes.
Service with some freshly prepared basmati rice (I like Tilda Wholegrain basmati rice) or with chapatti breads.