1. Preheat oven to 350 degrees Fahrenheit.
2. In a medium-sized bowl, combine 3/4 cup white sugar, flour, 1/4 cup cocoa, baking powder, and salt. Add soy milk, chocolate liqueur, vanilla extract, and margarine. Mix until smooth. Pour into ungreased eight-inch square pan.
3. In a medium sized bowl, stir together the remaining 1/2 cup sugar, brown sugar, and remaining 1/4 cup cocoa. Sprinkle mixture evenly over the batter. Pour hot water over the top; do not stir.
4. Bake 40-45 minutes or until the center is almost set. Remove pie from the oven, and let stand for 15 minutes.
5. Serve warm, on individual plates, spooning the sauce on the bottom of the pan to over the top. Top with whipped cream.