1 cup boiling water
2 teaspoons baking soda
2 1/2 cups all-purpose flour
2 teaspoons ground ginger
1 1/2 teaspoons cinnamon
1/2 teaspoon nutmeg
1/2 teaspoon ground cloves
1/4 teaspoon allspice
3/4 teaspoon kosher salt
2 teaspoons baking powder
8 tablespoons unsalted butter, at room temperature
3/4 cup packed dark brown sugar
2/3 cup blackstrap molasses
1 tablespoons freshly grated ginger
2 tablespoons milk
2 eggs
1 cup diced cubed candied ginger
Confectioners' sugar, for dusting