Prepare the spinach first. If using frozen, let it defrost and squeeze out as much moisture as possible. If using fresh, blanch it in boiling water, drain, then again, squeeze out as much water as possible. Chop. 

Heat the oil in a non stick pan. Fry the paneer in batches, until it goes brown and crusty, before removing it from the pan and letting it drain on kitchen paper. 

Using the same pan, add the garlic, ginger, chilli and spices. Cook until the ginger and garlic are just beginning to brown, and the mustard seeds start to pop. 

Add the onion, and cook until translucent.

Add the spinach. Season, and stir until everything becomes combined. 

Finally, add the paneer back to the pan, and cook on a gentle heat until it reheats. 

And serve - this will serve 3-4 as a main, or up to 6 as a side dish.