I altered the original recipe to suit my tastes and, in my opinion, to make it easier to cook. I did make my own Madras Curry Powder. I had all the ingredients on hand and this allowed me to control the heat. Not that there is none, I did include the generous number of whole black pepper corn as well as the chili powder, so it does have some heat. But you can control this by increasing the quantity called for in the recipe, or add your own hot chili if you like the flavor.
I also substituted the fresh tomatoes that were originally called for with chopped canned tomatoes as I find that the flavor and color you get from canned is more predictable than using fresh.
Lastly, I also added tomato paste to counter balance the sourness of the canned tomatoes. This worked well to enhance the flavor of the tamarind sauce as well as the texture and color of the dish.