Preheat oven to 350°. Spray a 9"-by-9" pan with cooking spray and line with parchment, leaving an overhang on 2 sides.
In a medium bowl, whisk flour, ginger, baking soda, cinnamon, and salt. In a large bowl, using an electric mixer on medium-high speed, beat butter and brown sugar until creamy and lightened in color. Add egg, honey, and molasses and beat until combined.
Fold in dry ingredients until no streaks remain, then pour in boiling water and stir until incorporated. Pour batter into prepared pan.
Bake cake until risen, firm to the touch, and a tester inserted into the center comes out clean, 30 to 40 minutes. Let cool completely.
Using parchment overhang, lift cake out of pan and transfer to a platter. Serve topped with cream.
