First, add the oil to a large frying pan, add in the onion and fry for approx 8-10 minutes on a low to medium heat until soft and browning.
Now add the spices and garlic and stir for a minute.
Now add the lentils and water. Stir well then turn down the heat, simmer for 15 minutes, stirring occasionally. Add more water if needed.
Blitz half the carrots with the water in a food processor until you get a chunky paste.
Add to the pan with the lentils, stir to combine.
Simmer for another 5 minutes.
Season with the salt, pepper, chilli and garam masala.