In a large mixing bowl combine flour, baking soda, baking powder, salt, cinnamon, nutmeg, cloves and ginger. Stir well and set aside.
In a separate large bowl, combine softened butter with sugar and whip it together. (It may not be creamy, but will separate into very small clumps). Add the pumpkin and lightly beaten eggs. Mix it briskly. There will be small lumps that will disappear when baked. Stir in milk and mix again. Add dry ingredients and mix well.
Butter and flour a 9 x 13 inch baking pan. Bake at 350 degrees about 40 minutes, or until a wooden toothpick comes out dry and clean. Cover with foil so the moisture stays in when cooling. Once cool, spread with Butterscotch Frosting
Combine sugar, butter and cream in a small heavy bottomed saucepan. Cook over medium heat, stirring constantly, until mixture is well-blended, 1-3 minutes. Remove from heat and whisk quickly to blend thoroughly. Set aside
Pour the combined sugar, butter and cream (which is now butterscotch sauce) into a large bowl and add 3 to 4 cups of powdered sugar until mixture is a good spreading consistency. I ended up adding 3 1/2, then I waited until it cooled a bit to see if the consistency was good for spreading. Add the salt to taste (and remember the best dessert recipes are a perfect marriage between sweet and salty so don't skimp on the salt!). Spread it on the cooled cake and enjoy!