Preheat the oven properly – Set your oven to 350°F (175°C) and line a 9×13-inch pan with parchment paper, leaving an overhang for easy removal.

Prepare the shortbread base – Cream the softened butter and sugar together until smooth. Gradually mix in flour and salt until a soft dough forms.

Press crust evenly – Transfer the dough into the prepared pan and press it evenly into the bottom using your fingers or the back of a measuring cup. Make sure the surface is level for even baking.

Bake the crust first – Bake for 15–20 minutes until lightly golden around the edges. Remove from the oven but keep the oven on.

Prepare the lemon filling carefully – In a large bowl, whisk eggs and sugar until fully combined and slightly pale. Stir in lemon zest and freshly squeezed lemon juice.

Add flour gradually – Sift flour into the lemon mixture and whisk until smooth and lump-free. This prevents clumps in the filling.

Pour over warm crust – Carefully pour the lemon mixture over the pre-baked crust while it is still warm. This helps the layers bind together.

Bake until set – Return the pan to the oven and bake for 20–25 minutes. The center should be set but still slightly soft when gently shaken.

Cool completely – Allow the bars to cool at room temperature for at least 1–2 hours. Cooling is essential for clean slicing.

Dust and slice – Once fully cooled, dust with powdered sugar and cut into neat squares using a sharp knife wiped clean between cuts.