Preheat your oven to 350°F (180°C) and grease two 8x4 inch loaf pans.
In a large mixing bowl, whisk together the granulated sugar, sour cream, eggs, vegetable oil, lemon zest, lemon extract (if using), and vanilla extract (if using) until well combined.
In a separate bowl, sift together the all-purpose flour, baking powder, baking soda, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Be careful not to overmix.
Gently fold in the blueberries until evenly distributed throughout the batter.
Divide the batter evenly between the prepared loaf pans and smooth the tops with a spatula.
Bake in the preheated oven for about 50-60 minutes, or until a toothpick inserted into the center of the loaves comes out clean.
Allow the loaves to cool in the pans for about 10 minutes, then transfer them to a wire rack to cool completely.