Rinse the lentil thoroughly to remove the extra starch and set aside for 5 minutes.
In a medium sized pot, add the lentils with 4 cups of water and let it boil. Remove when it starts to foam up and then keep it boiling on medium heat for up to 20 minutes or until the water lessens to at least half.
Remove from heat and whisk. Return back to a medium heat and add the stock cube and salt. Add 2 tbsp of olive oil to a pan and add the diced onions, continue stirring until it turns light golden. Remove half of it and place it in a bowl, add the curry to the remaining half in the pan and stir for another minute, then add to the lentils.
Place 2 tbsp of olive oil in the pan and add the vermicelli to it (it should become light gold in colour). Add the turmeric and stir for 1 minute. Place all this in the lentil pot (notice that the vermicelli absorbs a lot of water hence you need to regularly check the water and add if necessary), add another cup of water and let it boil on low heat until all ingredients are combined.
Stir thoroughly to avoid lentil from sticking to the bottom of the pot. Add salt to taste and divide the soup between 4 bowls, place the remaining onions on a pan and let it fry until almost burned, remove from fire and use as garnish for the soup.