Preheat the oven to 350F.  Divide the 6 tablespoons butter and the brown sugar evenly between two round 9" baking pans.  Place each pan on a low setting on the stove and cook until the butter is melted.  Stir the brown sugar and butter together until combined and set aside.

In a small liquid measuring cup combine the boiling water and the baking soda, mix and set aside.

In a large mixing bowl using a hand-held electric mixer or Kitchen Aid mixer on medium setting, beat the 1/2 cup of butter and 2/3 cup of brown sugar together until fluffy.  Add the vanilla and then the eggs one at a time, beating well after the addition of each until mixed.  Add in the molasses and salt and continue to mix.  Sift in the flour, baking powder and gingerbread spice and mix until combined, scraping the sides of the bowl to make sure that everything is incorporated.  Slowly add in the water and baking soda mixture and mix again until combined.

Divide the batter evenly between each pan of the prepared pans, gently spreading to even the batter out over the pears if needed using a spatula.

Remove from the oven, allow to sit cool slightly, and carefully invert onto two separate serving plates or platters of your choice.  The easiest way to do this is to put the plate upside down on top of the pan, and using oven mitts, flip over the pan and carefully remove the pan from the plate once you flip it over.