Prepare the Blueberry Bread Batter:

1. Preheat the Oven: Preheat your oven to 350°F (175°C). Grease a standard 9×5-inch loaf pan or line it with parchment paper for easy removal.
2. Mix Dry Ingredients: In a medium-sized bowl, whisk together the flour, baking powder, baking soda, and salt until well combined.
3. Mix Wet Ingredients: In a large bowl, whisk together the oil and granulated sugar until smooth. Add the eggs, one at a time, beating well after each addition. Stir in the vanilla extract and buttermilk until fully incorporated.
4. Toss Blueberries in Flour: In a small bowl, toss the blueberries with 1 tablespoon of flour. This helps prevent the blueberries from sinking to the bottom of the loaf during baking. Gently fold the blueberries into the wet mixture.
5. Combine Wet and Dry Ingredients: Gradually add the dry ingredients to the wet ingredients, folding with a spatula or spoon until just combined. Be careful not to overmix, as this can lead to dense bread.
6. Transfer to Pan: Pour the batter into the prepared loaf pan. Use a spatula to smooth the top so that it bakes evenly.

Bake the Blueberry Bread:

7. Bake the Bread: Place the pan in the preheated oven and bake for 55-60 minutes, or until the bread is golden brown on top and a toothpick or cake tester inserted into the center comes out clean or with a few moist crumbs.
8. Cool the Bread: Allow the bread to cool in the pan for about 10 minutes. Then transfer it to a wire rack to cool completely. While the bread is cooling, prepare the lemon glaze.

Prepare the Lemon Glaze:

9. Make the Lemon Glaze: In a small bowl, whisk together the powdered sugar, lemon juice, and lemon zest (if using) until smooth. The glaze should be thick but pourable. If it’s too thick, you can add a little more lemon juice, a teaspoon at a time, until you reach the desired consistency.

Finish the Bread:

10. Glaze the Bread: Once the bread has cooled completely, drizzle the lemon glaze over the top, letting it drip down the sides. You can use a spoon or a small piping bag to evenly distribute the glaze.
11. Serve and Enjoy: Let the glaze set for about 10 minutes before slicing the bread. Cut into slices and serve as a delicious treat for breakfast, dessert, or a snack!