Cut the potatoes into chunks, and boil in a large pan of water until nearly soft.
Meanwhile, heat the oil in a large, deep frying pan, and add the sliced onion and Quorn pieces. Cook over a medium heat for 5 minutes, until just turning golden. Add the garlic and ginger, along with the curry powder, garam masala, ground cumin and cardamom seeds, and cook for another 2 minutes.
When the potatoes are cooked, drain them and add them to the pan along with the chopped tomatoes, vegetable stock, and peas. Bring to a gentle simmer, and allow to cook for at least 10 minutes, or until you're ready to eat. Serve hot, topped with plenty of fresh coriander