Heat the oil in a large frying pan, and add the Quorn (or whatever protein you’re using) and chopped onion. Cook for a few minutes over a medium heat, until the onion is fairly soft. Add the peppers and garlic, and cook for a couple more minutes. Next add the mushrooms and tenderstem broccoli, and cook for a few more minutes until the mushrooms are soft.
Add the spices, coconut, and sugar to the pan, and mix well to coat. Add the sultanas and vegetable stock, and bring to a simmer. Cook for 5 minutes until the vegetables and Quorn are fully cooked.
In a small bowl, combine the Greek yogurt with the cornflour, and mix to combine.
Just before you're ready to serve, remove the curry from the heat, and allow it to cool for a minute or two. Add a tablespoon or so of the liquid to the yogurt and cornflour mixture, and mix well. Repeat this a couple of times.
When the curry has cooled for a couple of minutes, add a dollop of yogurt, and gently mix it in. Repeat until you've added all of the yogurt.
Season with plenty of black pepper, and serve topped with chopped coriander.