Preheat the oven to 325°F and set an oven rack in the middle position. Generously grease loaf pans with baking spray, such as Pam. Place the 6 mini loaf pans on a cookie sheet so it is easy to place in oven.

In a medium bowl, combine the flour, salt, baking soda, baking powder, and pumpkin pie spice. Whisk until well combined; set aside.

In a large bowl of an electric mixer, beat the butter and sugar on medium speed until just blended. Add the eggs one at a time, beating well after each addition. Continue beating until very light and fluffy, a few minutes. Beat in the pumpkin. The mixture might look grainy and curdled at this point -- that's okay.

Add the flour mixture and mix on low speed until combined.

Turn the batter into the prepared pans, dividing evenly, and bake for 50 – 60 minutes, or until a cake tester inserted into the center comes out clean. Let the loaves cool in the pans for about 10 minutes, then turn them out onto a wire rack to cool completely.