Cream together sugars and butter in a large mixer bowl
Measure the buttermilk into a liquid measuring cup and add the baking soda then slowly add to sugar and butter mixture
In a medium bowl mix together (by hand) the pumpkin and egg - then add it to the sugar mixture.
Place flour, baking powder, spices, and chopped nuts in a medium bowl and mix by hand
Alternate adding the flour mixture and the buttermilk mixture beginning with the flour.
Scraping down the sides of the mixing bowl as you add ingredients
Add cake batter to a greased 9" x 5" loaf pan
Bake for 65 to 75 minutes
Brown Sugar Frosting
Add to a medium saucepan over medium-high heat:I cup brown sugar 1 Tablespoon butter⅓ cup milkBoil for one minute then remove from heat and cool 3 minutes. Place in a mixer bowl and add 2½ to 3 cups of 10x sugar.Spread on top of loaf cake and garnish with additional chopped nuts.Note: double this recipe if making a layered cake.