In a heavy saucepan over medium heat, melt the sugar. Stir often to avoid burning. As the sugar becomes liquid, reduce heat to medium-low and stir constantly to avoid burning.
Transfer to a flan pan or ramekins and set aside.
Beat eggs. Blend in Condensed Milk, Evaporated Milk, 15oz, Pumpkin Puree, and vanilla until smooth. (This may be done with an electric mixer or in a blender.) Add to pan and cover.
Place flan pan or ramekins in a large roasting pan. Fill the pan halfway up with water. Carefully move to preheated oven. Bake for 60 to 90 minutes, until set. (The amount of cooking time will depend on the size of your containers.)
Remove from water bath. Chill for several hours or overnight.
Run a paring knife around the edges. Tilt upside down on a plate.