The addition of cocoa powder to this classic recipe yields a more complex and deeper flavor.
It is delicious served warm with a dollop of whipped cream.
Preheat the oven to 350 degrees F. Butter the bottom and sides of an 8-inch square baking pan. Dust with flour and tap out the excess.
In a medium bowl, use a wire whisk to stir together the flour, ginger, baking powder, cinnamon, allspice, baking soda and salt.
Put the cocoa powder in a small bowl. Stir in 1/3 cup boiling water and whisk until smooth.
In an electric mixer, cream the butter and sugar until the mixture is light and fluffy. Add the eggs, one at a time, beating well after each addition. Beat in the molasses, then the cocoa mixture. Reduce the speed and mix in half the flour mixture until just well-combined. Beat in the remaining 1/3 cup boiling water, then the remaining flour mixture. Do not overbeat.
Pour the batter into the prepared pan. Bake for 40 to 45 minutes, until a cake tester or toothpick inserted in the center of the cake comes out dry and clean.
Set the gingerbread on a wire rack to cool slightly.
If desired, serve with whipped cream. In a chilled bowl using a hand-held mixer or a wire whisk, beat the cream and sugar (optional) until the mixture forms soft peaks. Do not overbeat.
Cut the gingerbread into squares and serve warm, with a dollop of the whipped cream.