Preheat the oven to 350°F (175°C). Thoroughly grease two 9-by-5-inch loaf pans. For easier removal, the pans may also be lined with parchment paper.

Place the softened butter, room-temperature cream cheese, and granulated sugar in a large mixing bowl. Beat at medium speed until the mixture becomes pale, smooth, and fluffy.

Blend the vanilla extract into the creamed mixture. Add the eggs individually, beating well after each addition so that every egg is fully incorporated before the next is introduced. Scrape the sides and bottom of the bowl when necessary.

Gradually add the 2 cups of all-purpose flour, baking powder, and salt to the wet mixture. Mix at low speed, or stir by hand, only until the dry ingredients are incorporated. Avoid excessive mixing to preserve the bread’s tender texture.

Toss the fresh blueberries with the remaining tablespoon of flour until lightly coated. Using a spatula, carefully fold the berries into the thick batter without crushing them.

Distribute the batter evenly between the two prepared loaf pans. Transfer both pans to the preheated oven and bake for approximately 50 minutes.

Test the loaves by inserting a toothpick into the center. They are fully baked when the toothpick emerges clean or carries only a few moist crumbs.

Remove the pans from the oven and allow the loaves to cool inside them for 10–15 minutes. Run a knife gently around the edges, then carefully lift or turn the breads out of the pans. Continue cooling before slicing and serving.