Preheat your oven to 350°F (175°C). Grease and flour a 9x5 inch loaf pan.
In a large mixing bowl, cream together the softened butter and granulated sugar until light and fluffy. This should take about 3-5 minutes.
Add the eggs one at a time, mixing well after each addition.
In a separate bowl, whisk together the flour, baking powder, baking soda, and salt.
Gradually add the dry ingredients to the butter mixture, alternating with the sour cream. Start and end with the flour mixture. Mix until just combined.
Fold in the lemon zest and lemon juice gently until evenly distributed.
Finally, coat the blueberries in a light dusting of flour (to prevent sinking) and fold them into the batter carefully.
Pour the batter into the prepared loaf pan and smooth out the top.
Bake in the preheated oven for 60-70 minutes or until a toothpick inserted into the center comes out clean.
Once baked, allow the cake to cool in the pan for about 10 minutes before transferring it to a wire rack to cool completely.
Notes
Dust with powdered sugar before serving and garnish with fresh blueberries and a slice of lemon for an eye-catching display.