Place the lentils in a strainer and rinse under cool water. Set aside.

Heat the oil in a medium pot over medium heat. Fry the onion until soft and transparent then add the ginger and garlic and fry for another 30 seconds to a minute until soft and fragrant.

Add the tomato paste and stir well. Fry, stirring frequently, until the tomato paste darkens slightly in color - about 2 minutes. Add in the curry powder, cayenne pepper and garam masala and cook, stirring, for another minute or until the spices are fragrant.

Add in the lentils, vegetable broth and salt. Bring to a boil then reduce the heat to a gentle simmer and partially cover the pot with the lid.

Simmer gently until the lentils are tender and most of the broth is absorbed - about 15 to 20 minutes.

Serve with rice and garnish with fresh cilantro and a slice of lime, if desired.