Soak the lentils for an hour. This is not necessary but I find that it helps to speed up the cooking process.
Cook the lentils in about 2-3 cups of water. Bring the water to a boil and then simmer for about 15-20 minutes until the lentils get a texture of what in the Pasta world we call as 'Al dente'. Cooked but with a bite in it still.
Meanwhile heat about 2 tsp of oil or butter in a skillet. Once hot add the sliced onions to it
and cook until browned and caramelized. This takes about 10 minutes. Remove from the pan and set aside.
In the same pan, add 1/2 tsp oil (if needed) and add the shallot or use little of red/white onion (whatever you have in hand). Add salt and cook for 1 minute
Add the rice and cinnamon stick and cook until the rice is aromatic and toasted.
Add 2 cups of water, cover and cook rice - about 10-15 minutes.
When the rice has absorbed all the liquid and is almost cooked, add the cooked lentils, zest and juice of lemon to this mixture. Cook for another 3-4 minutes for the rice to absorb the flavors of the lentils.