For the Flapjack: Preheat the oven to 160°C Fan/Gas Mark 4. Combine the wet mix ingredients in a large non-stick saucepan. Heat gently until melted.
Combine all dry ingredients in a large mixing bowl and stir. Remove wet mix from heat, and combine with the dry mix. Spoon the mixture into an 8’’ shallow square loose-bottomed tin, greased and lined with parchment paper.
Level and press firmly with a palette knife to smooth. Bake on the middle shelf for 25 minutes, until golden brown on top.
Remove from oven and leave to cool in the tin for 10 minutes. Cut into squares while still warm and leave to cool for a further 15 minutes.
Lift out of the tin to cool completely on a wire rack and discard the parchment paper.
For the Caramel and Garnish: Combine Lyle’s Golden Syrup®, sugar, butter and whole milk in a large non-stick saucepan. Bring to a gentle boil and whisk continuously. Leave on the heat until mixture reaches 150°C, at which point reduce the heat.
Meanwhile, place whipping cream in a separate sauce pan and bring to the boil. Slowly mix the boiling cream into the toffee mixture until it is fully combined.
Pour the mixture into an 8’’ square cake tin, lined with parchment and refrigerate for 2 hours to set.
Remove from the fridge and allow the mixture to soften at room temperature. Remove from cake tin and place a piece of parchment on top of the caramel. Roll out to 3-5mm thick.
Finally place the caramel layer on top on the flapjack, sprinkle over the garnish and cut into 12 equal portions before serving.