Make the curry powder by toasting the whole spices in a dry pan and grinding in a pestle and mortar. Combine with the ground spices.
Heat a large pan over a medium heat and add the oil. When the oil is hot, add the onions, and gently soften them with a pinch of salt. When the onions have begun to soften, add the spring onions, peppers, scotch bonnet, garlic, and ginger. Cook for another minute.
Add the thyme leaves and 1 tablespoon of curry powder. Cook for 1 minute then add the tomato puree. Add the tinned tomatoes. Bring to a boil, then reduce to a simmer.
Bring to a boil, and reduce to a simmer. Add the potatoes and cook for 20 minutes until the potatoes are almost tender.
Add the Drained black beans and coconut milk and cook for another 10 minutes.
Serve garnished with chopped coriander.