Just made this, and eating it right now. Yummy.
Better to light a candle than to curse the darkness, or so I believe. Therefore:
To prevent yogurt from curdling in curries, add only a tablespoon at a time and stir it in gently and fully before adding the next tablespoon. In this recipe it would be better to incorporate the yogurt before adding the tofu to prevent damaging your cubes.
Curry Powder, yes, indeed, no self respecting curry chef will have any such thing in their cupboard. I used 2 tsp cumin, 2 tsp coriander, 1/4 tsp turmeric, 1/8 tsp cayenne, and topped it after with 1/4 tsp garam masala. You could tone it down a bit but why? You're making curry.
The recipe will benefit from a bit of coconut milk, no more than a half cup would add the proper creamy texture.
Oil/Nonstick Pan: you can cut the oil by 3/4 by using Pam or oil sprayed with a spritzer and a well seasoned black iron pan. More authentic to use black iron. Of course in India it would have more oil, but you don't need to, if you've seasoned your pan well.
Salt: The dish tastes wonderful without any added salt. Give it a try; your body will be pleased.
Been to the subcontinent several times and eaten more than my share of paneer, saag, and curry. This is a good recipe