In a small sauté pan, heat the oil over medium-low heat. Add the garlic and spices and cook until the garlic is soft, about 5 minutes. Be careful not to burn the garlic! Scrape the mixture into a slow cooker (one with at least 5 quart capacity).
Add the stock, vegetables, tomatoes, beans, currants, and nuts. Set the cooker on low and cook until the vegetables are tender, about 8 to 9 hours.
Remove about 3 cups of the cooked mixture to a blender or food processor, and carefully puree. Return to the slow cooker, stir, and season to taste with sea salt and fresh pepper. Serve with a dollop of yogurt.