Preheat your oven to 350°F (175°C). Grease and flour a 9x5 inch loaf pan. Spread chopped pecans on a baking sheet and toast for 5-7 minutes until fragrant. Set aside to cool.

In a medium bowl, whisk together the flour, baking powder, baking soda, and salt.

In a large bowl or the bowl of a stand mixer, beat the softened butter, brown sugar, and granulated sugar on medium-high speed for 3-4 minutes until light and fluffy.

Add the eggs one at a time, beating well after each addition. Scrape down the sides of the bowl as needed. Mix in the vanilla extract.

With the mixer on low, add the dry ingredients in three parts, alternating with the buttermilk in two parts, beginning and ending with the dry ingredients. Mix only until just combined.

Gently fold in the cooled, toasted pecans. Pour the batter into the prepared loaf pan and smooth the top.

Bake for 55-65 minutes, or until a wooden skewer inserted into the center comes out clean. Let the cake cool in the pan for 15 minutes, then invert it onto a wire rack to cool completely.

To make the glaze, melt the butter in a small saucepan over medium heat. Cook until it foams and brown specks appear at the bottom. Immediately pour into a heatproof bowl. Whisk in the sifted powdered sugar, vanilla, and 1 tablespoon of milk. Add more milk as needed to reach a drizzling consistency.

Drizzle the glaze over the completely cooled cake. Let the glaze set for 20-30 minutes before slicing and serving.