- Melt the butter in a deep pan. Add the onions, garlic and ginger and cook for 5 minutes until golden but without burning the butter.
- Add the spices and bay leaves and cook, stirring, for 2-3 minutes more.
- Cut the larger mushrooms into big pieces but leave oyster mushrooms whole. Add mushrooms to pan and cook for a few minutes until they soften.
- Add 225 ml of water and the nuts. Bring to the boil, reduce heat and simmer, covered, for 15 minutes.
- Wash the spinach and put in a separate saucepan to cook in its own steam. Cook for 2 minutes until wilted. Drain and squeeze out the water.
- Stir the spinach and sultanas into the curry and simmer for 2 minutes.
- Mix the yoghurt and crème fraiche together and stir into the mushrooms, bringing them almost to the boil.
- Season to taste then stir in the chopped coriander and serve.