Gluten-Free Pumpkin Bread with Buttermilk

Preheat the oven to 350 degrees F (175 degrees C). Lightly butter an 8 1/2x4 1/2-inch loaf pan.

Whisk flour, baking powder, baking soda, cinnamon, salt, and nutmeg in a bowl.

Beat sugar and butter using an electric mixer in a large bowl on medium-high speed until light and fluffy, about 7 minutes. Add eggs, 1 at a time, beating well after each addition and scraping down the bowl as needed. Beat in vanilla extract. Add flour mixture gradually while beating on low speed; beat until just combined. Add pumpkin and buttermilk and beat until just combined.

Transfer batter to the prepared loaf pan and smooth the top.

Bake in the preheated oven until a toothpick inserted into the center comes out mostly clean with a few moist crumbs attached, about 1 hour and 15 minutes.

Remove from the oven and let cool in the pan on a wire rack for 15 minutes. Turn loaf out onto the rack and let cool completely, 15 to 30 minutes more.