COLONIAL SOFT GINGERBREAD

From 1922:

One cup brown sugar, 1 tablespoon butter, 1 egg, 3 cups flour, 2 teaspoons cinnamon, 1 ½ teaspoons ginger, 1 ½ teaspoons allspice, 1 1/3 cups buttermilk, 2 teaspoons soda, ¼ cup hot water, 1 cup molasses. Cream the butter and sugar together, then add the egg well beaten. Sift the flour with the spices, and add alternately with the buttermilk to which the soda dissolved in hot water has already been added. Bake in a flat paper-lined tin.