Step 1

Preheat your oven to 350°F. Grease and line a standard 9-inch x 5-inch loaf pan and set it aside.

Step 2

In a large bowl, place the flour, xanthan gum, cornstarch, salt, baking powder, baking soda, pumpkin pie spice and sugars, and whisk to combine well, breaking up any lumps in the brown sugar.

Step 3

Create a well in the center of the dry ingredients, and add the butter, eggs, buttermilk and pumpkin butter, and mix until smooth and uniform in color.

Step 4

The batter will be very thick. You can try using a handheld mixer to ensure a smooth, even batter. It will climb up the beater blades, so just keep scraping it down and carry on.

Step 5

Scrape the batter into the prepared pan, pressing it into all corners of the pan so there aren’t any gaps in the baked bread.

Step 6

With wet fingers and/or a wet spatula, smooth the top of the batter into an even layer and score it about 3/4-inch deep along the length, down the center of the bread using a sharp knife at a 45° angle.

Step 7

Dust the top generously with a layer of the (optional) cinnamon sugar mixture, and score again down the center if necessary to reestablish the scoring.

Step 8

Place the loaf pan in the center of the preheated oven and bake until the top is domed and lightly golden brown, and a toothpick inserted in the center comes out with no more than a few moist crumbs attached (nothing gooey at all!) (45 to 55 minutes).

Step 9

Remove the pan from the oven and allow to cool for 10 minutes before turning out onto a wire rack to cool completely. Slice and serve once cool.