Follow these simple steps to create your Easy Blackberry Pistachio Dessert Bars:

1. Preheat the Oven: Preheat your oven to 350°F (175°C). Grease a 9×9-inch baking pan or line it with parchment paper.

2. Mix Dry Ingredients: In a medium bowl, whisk together the flour, granulated sugar, baking powder, and salt until well combined.

3. Combine Wet Ingredients: In another bowl, mix the melted butter, eggs, and vanilla extract until smooth.

4. Combine Mixtures: Gradually add the wet ingredients to the dry ingredients, stirring until just combined. Do not overmix.

5. Add Blackberries and Pistachios: Gently fold in the fresh blackberries and chopped pistachios, being careful not to crush the berries.

6. Prepare Cream Cheese Layer: In a separate bowl, beat the softened cream cheese with powdered sugar until creamy. Drop spoonfuls of this mixture over the batter and swirl with a knife for a marbled effect.

7. Bake: Pour the batter into the prepared baking pan. Bake in the preheated oven for 30-35 minutes, or until a toothpick inserted in the center comes out clean.

8. Cool: Allow the bars to cool in the pan for about 1 hour before cutting into squares.