This is a recipe for the dry lentils as bought in an English supermarket.
I often substitute a ½ teaspoon of cinnamon powder instead of using a cinnamon stick. I also often add ½ teaspoon each of coriander, cumin and garam masala. As the lentils when cooked are not of a thick consistency, in order to correct this, I use 1 large onion and brown it before I begin to add the spices.

Taken from : Madhur Jaffrey’s book, An Invitation To Indian Cooking.

Serves 6-8

Ingredients:
Lentils 1 lb
Cinnamon stick, 2-3 inches long 1
Bay leaf 1
Garlic cloves, peeled 5
Ginger, peeled, 1/8 inch thick, 2 slices and about 1 inch in diameter
Turmeric(ground) 1 tsp
Lemon 3/4
Salt 1 1/2 tsp
Freshly ground black pepper 1/8 tsp
Cayenne pepper(optional) 1/4 -1/2 tsp
Vegetable oil or usli ghee 3 tbs
Ground Asafetida or tiny lump asafetida a pinch
Whole cumin seeds 1/2 tsp
Method:

Place washed lentils in a pot with sufficient water and a bay leaf and boil for 30 minutes or till tender. My adapted version slightly differs to the ingredients above, you may try whichever you fancy?! I heat oil and add the asafetida and cumin seeds and then add 1 onion and fry that till golden brown. Then I add the chopped ginger and garlic, as well as the ground spices, which for me are 1/2 tsp of cinnamon powder, instead of the cinnamon stick and 1/2 tsp each of cumin, coriander and garam masala powder, along with the tumeric and red chili powder as well as black pepper powder. I then add 2 pureed tomatoes[ instead of lemon slices]. I combine the vaghar with the cooked and soft lentils and simmer together for a few minutes till you get the desired consistency you like.