Preheat your oven to 350°F (175°C) and grease a standard loaf pan.
Place the butter in a saucepan over medium heat; whisk constantly until it foams, turns amber, and releases a nutty aroma.
Immediately remove the browned butter from the heat and transfer it to a bowl to cool slightly.
In a bowl, whisk together the flour, pumpkin spice, baking soda, and salt.
In a separate large bowl, beat the cooled browned butter with the brown sugar until smooth.
Add the eggs to the butter-sugar mixture one at a time, beating well after each addition.
Stir in the pumpkin puree until well combined.
Gradually fold the dry ingredients into the wet ingredients, mixing only until just combined to ensure a tender crumb.
Pour the batter into the prepared loaf pan and smooth the top.
Bake for 60 minutes or until a skewer inserted into the center comes out clean.
Allow the bread to cool in the pan for 10 minutes before transferring to a wire rack.