Put the onion, ginger, jalapeno, cashews, and garlic into a food blender with ½ cup of water and blend until it becomes a purée.
Heat the olive oil over a medium heat. As this is heating, place the spices in a bowl.
Pour the purée mixture into the hot pan. Stir in the spices and cook roughly 2 or 3 minutes until fragrant.
Add the tomato, diced potato, peas and carrots, green beans, coconut milk, yoghurt, and brown sugar. Stir well, cover and allow to simmer over a medium heat for about 10 minutes.
Remove the lid and cook until the potatoes are tender (5 to 10 minutes).