Preheat your oven to 350°F and grease a 9×5 inch loaf pan.
In a small saucepan over medium heat, melt the butter and continue cooking until it turns golden brown and smells nutty. Set aside to cool.
In a large mixing bowl, whisk together the pumpkin puree, maple syrup, eggs, and vanilla extract.
Add the brown butter to the wet ingredients and whisk until well combined.
In a separate bowl, sift together the whole wheat pastry flour, baking soda, baking powder, cinnamon, nutmeg, and salt.
Gradually fold the dry ingredients into the wet mixture until just combined, being careful not to overmix.
Pour the batter into the prepared loaf pan and smooth the top.
Bake for 50-60 minutes, or until a toothpick inserted into the center comes out clean.
Allow to cool in the pan for 10 minutes before transferring to a wire rack.
Once fully cooled, whisk the glaze ingredients together and drizzle over the top of the bread.