#### Step 1: Preheat and Prepare
Preheat your oven to 350°F (175°C).
Grease and flour a 9x5-inch loaf pan or line it with parchment paper for easy removal.
#### Step 2: Mix the Dry Ingredients
In a medium bowl, whisk together flour, baking powder, baking soda, and salt. Set aside.
#### Step 3: Cream the Butter and Sugar
In a large bowl, beat the softened butter and sugar together until light and fluffy, about 2–3 minutes.
#### Step 4: Combine Wet Ingredients
Add eggs one at a time, beating well after each addition.
Stir in vanilla extract.
#### Step 5: Alternate Dry and Milk
Gradually mix the dry ingredients into the wet ingredients, alternating with milk. Start and end with the dry ingredients. Mix until just combined—do not overmix.
#### Step 6: Fold in Blackberries
Toss the blackberries with 1 tbsp of flour to prevent them from sinking.
Gently fold the blackberries into the batter.
#### Step 7: Bake
Pour the batter into the prepared loaf pan and smooth the top.
Add a few blackberries on top for a decorative touch.
Bake for 50–60 minutes, or until a toothpick inserted into the center comes out clean.
#### Step 8: Cool and Serve
Allow the bread to cool in the pan for 10 minutes before transferring to a wire rack to cool completely.
Slice and serve warm or at room temperature.