I do a chick pea and potato curry, which you can cook with or without tomatoes:
oil in large pan, 1 tsp cumin seeds until the pop, add a large chopped onion or two, frey until softened, add potatoes, peeled and diced into 2cm cubes, stir fry for a few minutes, add some water, about a glassfull. stir, add tinned chickpeas, or soaked and cooked dried ones, 1/2 tsp tumeric, 1 tsp chilli, 1-2 tsp salt, stir well, simmer until almost soft, then add 1 heaped tsp each of ground cumin and coriander seeds.
For a lovely sour spicy taste, add more water and simmer until the potatoes are almost cook, add a couple of tablespoons of tamarind paste, and at the end of cooking add 1 - 2 tsp of garam masala.
For a tomato sauce, add 1 tin of chopped plum tomatoes, or 2-3 chopped fresh ones, simmer until cooked and finish with garam masala.
Serve either version garnished with chopped fresh coriander with rice or indian breads or on it's own. It's lush with crisps crushed over the top, and lemon juice squeezed over the top - Yum!