Butter and flour the sides (not the bottom) of a 9-inch round cake pan that’s 3 inches deep, tapping out the excess flour. To make the butterscotch, in a small saucepan, melt the 6 Tbs. butter with the brown sugar, stirring for a smooth mixture. Pour the mixture into the cake pan and swirl it to cover the bottom.
Heat the oven to 300°F. In a bowl, sift together the flour, baking powder, salt, ginger, cinnamon, and cloves. Using the paddle attachment of an electric mixer, cream the butter and sugar until light and fluffy; set aside.
With a fork, stir 1 tsp. of the baking soda vigorously into the molasses until the molasses has lightened somewhat and has changed in texture; this can take a minute or two. Add the molasses to the butter-sugar mixture and mix on medium until completely combined. Add the remaining 1/2 tsp. baking soda to the boiling water. On low speed, alternately add the dry ingredients and the water to the buttermolasses mixture. Mix until just smooth. Finally, add the eggs one at a time, mixing to combine after each addition. The batter will be very thin.
Bake until the center of the cake is springy to the touch and a toothpick comes out clean, about 1 hour and 15 min. Let cool 5 min. and then invert the cake onto a serving plate. Let cool for an hour before serving; the cake will still be warm, which is how it’s best.
Just before serving, sauté the apples. Let them cool slightly. Top the cake with the warm apples and serve with some whipped cream, if you like.