Prepare the Pan and Preheat:

1. Preheat oven: Preheat your oven to 350°F (175°C). Line a 9×13-inch baking pan with parchment paper or aluminum foil, leaving overhang on two opposite sides for easy removal later. Lightly spray with non-stick cooking spray.

Make the Shortbread Crust:

2. Cream butter and sugar: In a large mixing bowl, beat the softened butter and powdered sugar together with an electric mixer on medium speed for 2-3 minutes until light and fluffy. The mixture should look pale and creamy.

3. Add vanilla: Mix in the vanilla extract until combined.

4. Add dry ingredients: Add the flour and salt to the butter mixture. Mix on low speed (or stir with a wooden spoon) until the mixture comes together and resembles coarse crumbs. It should hold together when pressed but still look crumbly.

5. Press into pan: Transfer the crust mixture to your prepared pan. Using your hands or the bottom of a measuring cup, press the mixture firmly and evenly into the bottom of the pan, making sure to reach all corners and edges. The crust should be compact and level.

6. Pre-bake crust: Bake the crust for 20-25 minutes until it’s lightly golden around the edges and set in the center. Don’t let it get too brown. Remove from oven and set aside. Keep the oven on at 350°F.

Make the Lemon Raspberry Filling:

7. Zest and juice lemons: While the crust is baking, zest your lemons using a microplane, being careful to only get the yellow part, not the bitter white pith. Then cut and juice the lemons, straining the juice through a fine-mesh sieve to remove seeds and pulp. You need ¾ cup of juice.

8. Whisk eggs and sugar: In a medium bowl, whisk together the eggs and granulated sugar until well combined and slightly thickened, about 1-2 minutes.

9. Add lemon: Whisk in the lemon juice and lemon zest until fully incorporated.

10. Add dry ingredients: In a small bowl, whisk together the flour, baking powder, and a pinch of salt. Add this to the lemon mixture and whisk until smooth with no lumps.

Assemble and Bake:

11. Pour filling: Pour the lemon filling over the hot, pre-baked crust. It’s okay that the crust is still warm—this actually helps the filling set properly.

12. Add raspberries: Gently scatter the fresh raspberries evenly over the top of the lemon filling. They’ll sink slightly into the filling, which is perfect. Try to distribute them somewhat evenly so every bar gets berries.

13. Bake: Carefully transfer the pan back to the oven and bake for 25-30 minutes. The filling is done when it’s set around the edges but still has a slight wobble in the very center (about a 2-inch circle). It will continue to firm up as it cools. The top should look matte, not wet.

Cool and Serve:

14. Cool completely: Remove from oven and place the pan on a wire cooling rack. Let cool to room temperature, about 1-2 hours. Don’t rush this step—the filling needs time to set completely.

15. Refrigerate: Once cooled to room temperature, cover the pan and refrigerate for at least 2 hours or preferably overnight. The bars must be completely cold before cutting for clean slices.

16. Cut and dust: Use the parchment overhang to lift the entire bar out of the pan onto a cutting board. Use a large, sharp knife (wiped clean between cuts) to slice into 16-20 bars, depending on your preferred size.

17. Dust with powdered sugar: Just before serving, dust the tops generously with powdered sugar using a fine-mesh sieve or small strainer. Serve cold or at cool room temperature and enjoy!