• Preheat the oven to 425°F. Line a 12-cup muffin pan with paper liners.

Make the Muffin Batter

• Melt the butter in a small saucepan over medium-low heat and then let it cool to room temperature. If the butter starts to splatter, reduce the heat to low.
• Place the all-purpose flour, baking powder, baking soda, and kosher salt in a medium bowl and whisk for 20 seconds to thoroughly combine all the ingredients.
• In a mixing bowl whisk together the brown sugar, granulated sugar, pumpkin pie spice, and ginger. Use your fingers to break up any clumps of brown sugar. Add the eggs and whisk for about 1 minute until the eggs are thoroughly incorporated. Whisk in the cooled melted butter.
• Next whisk in the pumpkin puree and buttermilk and let the wet ingredients sit for 5 minutes (and no more than 10 minutes) to give time for the sugar to dissolve.
• Add half of the flour mixture to the wet ingredients. Use a spatula to fold the dry ingredients into the wet ingredients. Add the remaining flour mixture and fold it in until the dry ingredients are thoroughly incorporated, and no white specs of flour remain. The batter may be a little lumpy which is okay.

Bake the Muffins

• Divide the batter between the 12 muffin cups. The batter should almost be the top of each paper liner. You will need to thoroughly scrape the bowl to completely fill the muffin cups.
• Bake the muffins at 425°F for 5 minutes, then without opening the oven door reduce the temperature to 350°F and bake the muffins until the center is done and the temperature in the center of the muffin registers at 202°F, 15-18 more minutes.
• Remove the muffin pan from the oven and let the muffins cool in the muffin pan for 5 minutes. Place the individual muffins on a wire rack to finish cooling. The muffins can be served warm.

Storage

• Store the pumpkin muffins in an airtight container for up to 3 days, and then store in the refrigerator for up to a week. The muffins can also be individually wrapped and frozen. When ready to eat reheat the frozen muffin in the oven.