Preheat oven to 375F (190C).Cut Cabbage into 8 wedges. Drizzle liberally with olive oil to coat. Place on a baking sheet covered with parchment paper. Roast cabbage in the oven until the edges are dark brown and crispy (about 1.5 hours).While the cabbage roasts, add all of the ginger-garlic stock ingredients to a lidded pot and bring to a simmer. Simmer until garlic is completely softened. About 30 minutes. Strain the stock with a sieve, retaining the garlic. Peel the garlic and force it through the mesh of the sieve into the stock with a spoon. Keep stock covered and on low heat.Also while the cabbage roasts, melt two tablespoons of butter in a heavy skillet. Add the leeks and braise, covered, over very low heat until the leeks are very, very soft. Stir frequently to keep from burning. Over low heat this should take about 30 or 40 minutes. Add the smoked paprika for the last five minutes of cooking. When finished the leeks will be very soft and lightly browned.Transfer the leeks to a bowl and in the same skillet melt the remaining two tablespoons of butter over medium heat. Add the pears. Allow to saute without stirring for five or six minutes to caramelize the sugar. Stir until pears are soft. Add them to the bowl with the leeks.In the same skillet cook the sausage over medium heat, breaking it up into small pieces. Set add to the leek and pear mixture.When the cabbage is finished roasting, allow to cool enough to handle. With a chef’s knife, cut the core pieces off and set aside. Thinly slice the cabbage wedges and add to the stock. Then add the leek, pear, and sausage mixture. Add additional water, as necessary, so stock just covers the cabbage mixture. Bring soup to a simmer, and allow to cook, covered, until cabbage is tender. About 15 to 20 minutes.Add the grapes to the soup mixture and cook for five minutes more.Serve in bowls with fresh grapes and fresh pear slices as a garnish.