Preheat the oven to 350°. Grease and flour two 8-by-3-inch loaf pans. In a large bowl, beat the eggs with an electric mixer until foamy. Beat in the molasses, brown sugar, butter and shortening. Sift in all of the dry ingredients and stir with a wooden spoon until incorporated. Stir in the boiling water until the batter is smooth.
Pour the batter into the prepared pans and bake for 35 to 40 minutes, or until a toothpick inserted in the center comes out clean. Let the loaves cool slightly in the pans, then turn them out onto a rack to cool completely.
The gingerbread can be well-wrapped and refrigerated for up to 1 week or frozen for up to 1 month.