Preheat oven to 350°F, placing the oven rack in the middle position. Grease a square 9-inch metal pan generously with butter. Optional: line with parchment paper and set aside.
In a large mixing bowl, add the softened butter and brown sugar. Using a hand mixer, beat until light and fluffy. Note: you can use a stand mixer if you prefer.
Add the egg and vanilla. Mix until combined. Then stir in the molasses until combined fully.
In another bowl, whisk together the flour, baking soda, ginger, cinnamon, cloves and salt.
Mix in ¼ of the dry ingredients into the batter using a wooden spoon. Then mix in about ⅓ cup boiling water.
Continue alternating by adding another ¼ of the dry ingredients followed by ⅓ cup boiling water until used up, finishing with the dry ingredients.
Pour the batter into the prepared pan. Bake for 30 to 40 minutes until the center is puffy and a cake tester or toothpick inserted into the middle comes out clean.
Cool in the pan for at least 20 minutes before cutting. Serve as squares with optional whipped cream on the side.