Made the base last week, but without the fenugreek and the madras powder because I couldn't find any in the stores, this is best explained by me being Swedish. I used it to try to improve one of my dullest curry attempts, that I had stored in the freezer. It definitely got better. Yesterday madras powder and fenugreek powder ordered online finally arrived and today I tried the recipe. However I forgot to buy fresh coriander so I had to make do with some dry leaves thrown into the mix. The result was good and felt a lot more like something I could receive in a Swedish Indian Restaurant than the usual stuff I make, however it wasn't quite there and I tried adding some (not much) lemon juice. I also added a bit of cardamom because my favourite indian place where I used to live have an extra cardamom touch to their madras, and one green chili pepper that was lying around, begging to be used. This, imo, made a good recipe even better, though the improvement might not have been needed if I had had the fresh coriander.
In short, good stuff, even though the extra touch that fresh coriander leaves always entails probably would have made it even better. The lemon juice was just a strange way of compensating, and the cardamom is just a question of taste and how your mind has been shaped by your local Indian restaurant. Great base and good madras.