2 cups all purpose flour
2 teaspoons pumpkin pie spice
1 teaspoon baking powder
3/4 teaspoon salt
1/2 teaspoon baking soda
6 tablespoons (3/4 stick) unsalted butter, room temperature
1 cup sugar
2 large eggs
1 cup canned pure pumpkin
1 teaspoon vanilla extract
2/3 cup buttermilk
1/2 cup dried sweetened cranberries
1/2 cup coarsely chopped walnuts
Preheat oven to 350 degrees F. Butter a standard loaf pan. Line bottom and 2 long sides with waxed paper. Whisk flour, pumpkin pie spice, baking powder, salt, and baking soda in medium bowl to blend. Using electric mixer, beat butter in large bowl until fluffy. Gradually add 1 cup sugar, beating until blended. Beat in eggs one at a time. Beat in pumpkin, then vanilla. Beat in dry ingredients alternately with buttermilk in 2 additions each. Fold in cranberries and nuts. Transfer batter to pan.
Bake bread until tester inserted into center comes out clean, about 1 hour 10 minutes. Cool bread in pan on rack 15 minutes. Cut around bread at short ends to loosen from pan. Turn bread out onto rack; peel off waxed paper. Cool bread completely.