Amy Roloff's Pumpkin Bread

      1 cup plus 4 tablespoons sour cream
      4 teaspoons baking soda
      2 teaspoons baking powder
      2 cups butter, room temperature
      4 cups granulated sugar
      2 (14.5-ounce) cans pumpkin puree
      1 tablespoon pumpkin pie spice
      1 teaspoon cinnamon
      1/2 teaspoon nutmeg
      1/2 teaspoon ground ginger
      4 eggs
      1/2 cup vegetable oil
      1/4 teaspoon pure vanilla extract
      8 cups all-purpose flour
      2 teaspoons baking powder
      1 teaspoon salt
      Toasted chopped walnuts, optional

      Makes approximately 2 to 3 loaves, depending on pan size. Halve the recipe if you do not want to make this much pumpkin bread.
      Preheat your oven to 350 degrees Fahrenheit. In a large mixing bowl, combine sour cream and baking soda; set aside. With a mixer, cream butter and sugar together until fluffy. Add sour cream mixture to the creamed butter on medium speed, mixing completely. In a small mixing bowl, combine pumpkin puree cinnamon, nutmeg, and ginger; whisk to combine. To pumpkin mixture, whisk in eggs one at a time, then add oil and vanilla. The batter should look a bit watery. Now add pumpkin mixture to the creamed butter mixture until well blended.
      Sift flour, baking soda, baking powder and salt into the pumpkin sugar mixture. Start mixer on low and then increase as flour is incorporated.
      Spray loaf pans with cooking spray and pour about 1/4 cup of sugar into each pan. Rotate until the sides of the pan are covered. Pour batter into loaf pans and top with toasted walnuts (if using). Bake for 35 to 45 minutes until golden brown or inserted knife comes out clean. Cool on racks for 45 minutes. Serve immediately or wrap with plastic wrap and store in the freezer.