Preheat the Oven:
Preheat your oven to 350°F (175°C). Grease a 9×5-inch loaf  pan and line it with parchment paper for easier removal.

Make the Bread Batter:
In a medium bowl, whisk together the flour, baking powder, baking soda, and salt.
In a large bowl, using an electric mixer, cream together the softened butter and sugar until light and fluffy. Add in the eggs, one at a time, beating well after each addition. Stir in the vanilla extract.
Gradually mix in the dry ingredients, alternating with the milk, starting and ending with the flour mixture. Mix just until combined. Fold in the floured blueberries gently.

Make the Cream Cheese Filling:
In a separate bowl, beat the cream cheese, sugar, egg, and vanilla until smooth and creamy.

Assemble the Bread:
Pour half of the bread batter into the prepared loaf pan and spread it evenly. Then, spread the cream cheese mixture evenly over the batter. Top with the remaining batter, carefully spreading it to cover the cream cheese layer.

Bake:
Bake for 55-65 minutes, or until a toothpick inserted into the center comes out clean. If the top starts to brown too much, cover it loosely with aluminum foil during the last 15 minutes of baking.

Cool:
Allow the bread to cool in the pan for 10 minutes before transferring it to a wire rack to cool completely.