In a small saucepan, heat molasses and 1/2 cup butter until almost boiling. Remove from heat and let cool slightly. Stir in baking soda, milk and egg.
In a large bowl, sift together flour, ginger, cinnamon and salt. Make a well in the center and pour in the molasses mixture. Mix until smooth.
Spray preheated waffle iron with non-stick cooking spray. Pour mix onto hot waffle iron. Cook until golden brown. Serve hot with chocolate sauce.
To make chocolate sauce: In a saucepan, combine water, 1 cup sugar, cornstarch, cocoa powder and 1 teaspoon salt. Cook over medium heat, stirring constantly, until mixture comes to a boil. Remove from heat and add vanilla and 2 tablespoons butter; stir until smooth.