1. Prepare the Crust:

1. Preheat oven to 350°F (175°C).
2. In a small saucepan, combine sugar and water over medium heat. Stir until sugar dissolves, then let it cook without stirring until it turns a deep amber color. Pour caramel into a 9-inch round baking dish, tilting to coat the bottom evenly.
3. In a blender, combine sweetened condensed milk, evaporated milk, pumpkin puree, eggs, vanilla, cinnamon, nutmeg, and ginger. Blend until smooth.
4. Pour the pumpkin mixture over the caramel in the baking dish. Place the dish in a larger roasting pan and fill the roasting pan with hot water halfway up the sides of the baking dish.
5. Bake for 50-60 minutes, or until the flan is set but still slightly jiggly in the center. Remove from the oven and let it cool to room temperature, then refrigerate for at least 4 hours or overnight.
6. To serve, run a knife around the edges of the flan and invert onto a serving plate. The caramel will drizzle over the top.