Preheat your oven to 350°F (175°C). Grease and flour the loaf pan.
In a mixing bowl, combine the flour, baking powder, baking soda, salt, and ground cinnamon. Whisk the dry ingredients together until well mixed.
In another bowl, cream the softened butter and granulated sugar using a rubber spatula or whisk until light and fluffy.
Add the eggs one at a time to the butter mixture, mixing well after each addition. Stir in the vanilla extract.
Gradually add the dry ingredients to the wet ingredients, alternating with the buttermilk. Mix until just combined, being careful not to overmix.
Fold in the chopped pecans gently with the spatula.
Pour the batter into the prepared loaf pan, smoothing the top.
Bake in the preheated oven for about 50 minutes, or until a toothpick inserted into the center comes out clean.
Once baked, remove the bread from the oven and let it cool in the pan for about 10 minutes before transferring it to a cooling rack to cool completely.