Preheat your oven to 350°F (175°C) and line a 9x13-inch baking pan with parchment paper.

In a mixing bowl, combine melted unsalted butter and granulated sugar until blended. Add the all-purpose flour until crumbly. Press into the bottom of the prepared pan and bake for 15 minutes.

In a large bowl, whisk together room-temperature eggs, granulated sugar, lemon juice, and lemon zest until smooth and well combined.

Gently fold in the fresh raspberries, slightly crushing them to release their juice, and then set aside.

Pour the raspberry-lemon filling over the crust and bake for an additional 25-30 minutes until the filling is set.

Let the bars cool completely at room temperature, then refrigerate for at least 2 hours before slicing.

Carefully lift the bars from the pan using the parchment paper and slice into squares. Dust with powdered sugar before serving.