Preheat your oven to 325 degrees Fahrenheit.
Grease a standard loaf pan thoroughly with butter or non-stick spray.
In a medium bowl, whisk together the flour, salt, and baking powder.
Beat the softened cream cheese and butter together in a large bowl until pale and fluffy.
Gradually add the sugar to the cream cheese mixture while beating on medium speed.
Add the eggs one at a time, beating well after each addition.
Stir in the lemon zest and lemon juice.
Gradually fold in the dry flour mixture until just combined.
Toss blueberries with a small amount of extra flour and gently fold them into the batter.
Pour the batter into the prepared loaf pan and smooth the top.
Bake for 60 minutes or until a toothpick inserted into the center comes out clean.
Allow to cool in the pan for 10 minutes before transferring to a wire rack.