Method

• 1.
  In a stand mixer fitted with the paddle attachment, cream together the butter, sugar and vanilla on a medium speed for about 5 minutes, or until pale and creamy.
• 2.
  Sift together the flour, cornflour and 1/2 tsp fine salt. The main objective here is to mix them well. The bran particles in the wholemeal flour won’t go through the sieve - just add them back in and mix well. Add the flour mixture to the creamed butter mixture in three increments, beating slowly between each addition. After the third addition, mix until just combined.
• 3.
  Tip the dough out onto a lightly floured bench and gently knead, just to bring it all together. Wrap the dough in plastic wrap and rest it in the fridge for at least 1 hour before using, or preferably overnight.
• 4.
  When you’re ready to bake, preheat oven to 180°C/160°C fan-forced. Line a baking tray with baking paper.
• 5.
  Place the dough on a lightly floured bench. Use a rolling pin to roll it into a rectangle 20cm × 15cm and 1.5cm thick. Cut it into 2 × 10cm rectangles. Cut each rectangle into 8 fingers.
• 6.
  Space your shortbread fingers out onto the baking tray and bake for 15 minutes. Rotate the tray in the oven and bake for another 2-5 minutes, until the edges are just starting to colour. Remove from the oven and sprinkle with caster sugar to finish. Cool on a wire rack before eating (although they’re lovely when still warm).