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

Prepare the bread batter: In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.

Mix the wet ingredients: In a separate large bowl, cream the softened butter and granulated sugar together until light and fluffy, about 3-4 minutes. Add the eggs, one at a time, beating well after each addition. Stir in the vanilla extract.

Combine wet and dry ingredients: Gradually add the dry flour mixture to the wet ingredients, alternating with the milk. Begin and end with the dry ingredients. Mix until just combined. Be careful not to overmix.

Toss the blueberries in flour: Toss the blueberries in the tablespoon of flour to prevent them from sinking to the bottom of the bread during baking. Gently fold them into the bread batter.

Make the cream cheese filling: In a separate bowl, beat together the softened cream cheese, granulated sugar, egg, and vanilla extract until smooth and well combined.

Assemble the bread: Pour half of the bread batter into the prepared loaf pan. Spread the cream cheese filling evenly over the batter. Then, top with the remaining bread batter, spreading it gently to cover the cream cheese layer.

Bake the bread: Bake in the preheated oven for 55-65 minutes, or until a toothpick inserted into the center comes out clean. If the bread is browning too quickly, tent it with aluminum foil and continue baking until done.

Cool and serve: Allow the bread to cool in the pan for 10-15 minutes before transferring it to a wire rack to cool completely. Slice and serve.