Preheat your oven to 350°F (175°C). Grease the 9x5 inch loaf pan or line it with parchment paper.
In a large mixing bowl, sift together the flour, sugar, baking soda, and salt.
In another bowl, whisk together the buttermilk, melted butter, eggs, and vanilla extract until combined.
Pour the wet ingredients into the dry ingredients. Gently mix with a rubber spatula until just combined. Do not overmix; it's okay if there are a few lumps.
Fold in the chopped pecans until evenly distributed throughout the batter.
Pour the batter into the prepared loaf pan, smoothing the top with the spatula.
Bake in the preheated oven for 55 minutes, or until a toothpick inserted into the center comes out clean.
Remove the bread from the oven and let it cool in the pan for about 10 minutes before transferring it to a wire rack to cool completely.