Paneer and peas

INGREDIENTS
groundnut oil or sunflower oil for frying
1 large onion, thinly sliced
2 large garlic cloves, coarsely chopped
1 green chilli, deseeded (optional) and chopped
1cm (1⁄2in) fresh root ginger, peeled and coarsely chopped
2 tsp garam masala
salt and freshly ground black pepper
400g can chopped tomatoes
225g (8oz) paneer, cut into bite-sized cubes
450g (1lb) frozen peas

METHOD
Heat a large, heavy frying pan over a medium heat. Add 3 tbsp of the oil. When the oil is hot, fry the onion, stirring frequently, for 8–10 minutes, or until dark golden brown. Do not let the onion burn.
Meanwhile, put the garlic, chilli, and ginger into a blender, and blend until a thick paste forms. Add the garam masala and season with salt and pepper.
Add the spice mixture to the fried onions and stir for a couple of minutes. Pour into a large, heavy saucepan, add the tomatoes and 150ml (5fl oz) water, and bring to the boil, stirring. Reduce the heat to low and leave to simmer and thicken while preparing the paneer, stirring.
Wash and dry the frying pan and place over a high heat. When the pan is hot, pour a thin layer of oil over the surface. Once hot, add as many pieces of paneer that will fit in a single layer and fry for 5 minutes, or until golden on all sides, using long-handled tongs to turn them. As the pieces are fried, transfer them into the simmering tomato mixture.
When all the paneer has been transferred, add the frozen peas to the saucepan, increase the heat and leave to cook for 5 minutes, or until the peas are cooked. Stir carefully to avoid breaking up the paneer. Taste and adjust the seasoning, if necessary.