Heat the olive oil in the insert pan of a slow cooker or a frying pan over medium heat. Add the onion, garlic, leek and carrot and sauté for 5–7 minutes, or until tender. Add the curry powder and stir for 30 seconds, or until aromatic.
Return the insert pan, if using, to the slow cooker, or transfer the vegetable mixture to the slow cooker. Add the split peas and stock. Cover and cook o