Creating Blackberry Pistachio Bars is a simple and straightforward process. Follow these steps for the best results:

1. Preheat Oven: Preheat your oven to 350°F (175°C). Grease and line an 8-inch square baking pan with parchment paper for easy removal.
2. Mix Dry Ingredients: In a mixing bowl, whisk together the flour, baking powder, and salt until well combined. Set aside.
3. Cream Butter and Sugar: In another large bowl, cream together the softened butter and granulated sugar until light and fluffy.
4. Add Egg and Vanilla: Beat in the egg and vanilla extract until fully incorporated.
5. Combine Mixtures: Gradually add the dry ingredients to the butter mixture, stirring until just combined. Be careful not to overmix.
6. Fold in Blackberries: Gently fold in the fresh blackberries, taking care to avoid crushing them.
7. Add Pistachios: Fold in the chopped pistachios, distributing them evenly throughout the batter.
8. Pour Batter: Pour the batter into the prepared baking pan, spreading it evenly.
9. Bake: Place the pan in the preheated oven and bake for 30-35 minutes or until the edges are golden and a toothpick inserted into the center comes out clean.
10. Cool: Once baked, allow the bars to cool in the pan for 15-20 minutes before transferring them to a wire rack to cool completely.
11. Dust with Powdered Sugar: If desired, dust the cooled bars with powdered sugar for an elegant finishing touch before slicing.