Preheat your oven to 325°F (160°C). Grease and flour a 9x5-inch loaf pan, ensuring it's well-coated to prevent sticking.

In a large mixing bowl, cream together the butter and sugar until light and fluffy. This usually takes about 3-4 minutes with an electric mixer on medium speed.

Add the eggs, one at a time, beating well after each addition. Stir in the vanilla extract.

In a separate bowl, whisk together the flour, baking powder, and salt. Gradually add the dry ingredients to the butter mixture, alternating with the milk. Mix until just combined, being careful not to overmix.

Gently fold in the blueberries until evenly distributed throughout the batter.

Pour the batter into the prepared loaf pan and spread it out evenly.

Bake in the preheated oven for 60-70 minutes, or until a toothpick inserted into the center comes out clean.

Allow the cake to cool in the pan for 10-15 minutes before transferring it to a wire rack to cool completely.