Michigan Navy Bean Soup

Heat oil in large ovenproof pot over high heat. Add onions and shallots, then cook them until brown, about 3 minutes. Add garlic, thyme, and rosemary then cook for 2 minutes. Add beans and water then bring to simmer. Generously season with salt and papper. Loosely cover with foil and transfer to lower rack of oven, cooking until tender, about 3 1.2 to 4 hours. Carefully remove from oven. Stir in red wine vinegar. Transfer ½ of beans in batches to a blender and puree till smooth then return to pot and stir. Serve with a dollop of sour cream and a sprinkling of chives.