I cook a nice spinach and lentil curry from an Anjum Anand book:

Put yellow lentil about 100g in water about 1l with some chopped ginger, turmeric and two whole chilliestake these out at the end.  Cook for 10 min
Blitz 2 skinned tomatoes and add these in - cook for another 20 min
Add spinach and salt or not and cook for about 10 more min - the lentils should start to break down by now.
At then end, fry some garlic, ground cumin, ground coriander and garam masala then stir this in.

I think thats about it - it is tasty but not hot. Obviously you can add or change most of the ingredients to your taste.