Preheat your oven to 350°F (175°C). This ensures that your bread bakes evenly.
Grease a standard loaf pan with cooking spray or butter to prevent the bread from sticking.
In a large mixing bowl, combine the all-purpose flour, baking powder, baking soda, and salt. Whisk them together until well combined.
In another bowl, combine the buttermilk, vanilla extract, vegetable or canola oil, and egg. Whisk until smooth.
Pour the wet ingredients into the dry ingredients. Gently stir with a rubber spatula until just combined. Be careful not to overmix; a few lumps are perfectly fine.
Gently fold in the blueberries until evenly distributed throughout the batter.
Pour the batter into the prepared loaf pan, smoothing the top with your spatula.
Bake in the preheated oven for 55-65 minutes, or until a toothpick inserted into the center comes out clean. If the top becomes too brown before the center is fully cooked, cover it loosely with aluminum foil.
Once baked, remove the bread from the oven and allow it to cool in the pan for about 10 minutes. Then, transfer it to a wire rack to cool completely.
