Preheat your oven to 350°F (175°C). Grease and line a 9x9-inch baking pan with parchment paper.

In a mixing bowl, whisk together the all-purpose flour, unsweetened cocoa powder, granulated sugar, and salt until well combined. Pour in the melted unsalted butter and mix until crumbly.

Evenly distribute the crust mixture into the bottom of the prepared baking pan. Press it firmly down and bake for about 10 minutes.

Melt the semi-sweet chocolate chips in a small saucepan over low heat, stirring until smooth.

In a separate bowl, whisk together the eggs and vanilla extract. Blend in the cooled melted chocolate until combined.

Gently fold the fresh raspberries into the chocolate mixture, being careful not to crush them.

Pour the chocolate-raspberry mixture over the cooled crust, spreading it evenly.

Bake for 30 to 35 minutes, until the edges look set and the center remains slightly moist.

Allow the pie bars to cool in the pan for about 15 minutes. Remove them using the parchment overhang and let them cool completely on a wire rack.

Once cooled, slice the bars into squares and dust with powdered sugar before serving.