Served with basmati rice.
Heat oil in a soup pot and saute onions for 5 minutes.
Add garlic and ginger and saute 5 more minutes.
Add spices and salt, saute 5 minutes more.
Add 4 cups of water and stir. Add tomatoes and lentils. Bring to a boil and then lower the heat a bit and simmer for 20 minutes.
About 25 minutes before serving, start the rice: rinse the basmati rice until the water runs clear, then bring it to a boil with the water and a pinch of salt. Cover, simmer on low for 15 minutes, then rest off the heat, covered, until serving.
Add the lemon juice and cilantro and more water if it's too thick. Simmer 10 more minutes, or until lentils are completely tender. This may take a while.