Wash the spinach and dry. Peel the onions and cut into thin rings. Peel ginger and finely grate. Peel the garlic and pass through the press. Melt the butter in a saucepan, fry onions until golden brown, add ginger and garlic, cook for 30 seconds, season with chili, cumin, turmeric and coriander, stirring, cook for a minute. Add spinach, reduce the heat, salt and cook under a cover for 15 minutes. Add cream, stir and serve.