Preheat the oven to 180°c (160 fan/ Gas 4/ 350F) and line a 20 x 30cm baking tin with baking paper.
Melt the butter, sugar and syrup in a saucepan over a low heat until everything is fully melted and combined. Leave to cool down for 5 minutes.
200 g Butter, 200 g Demerara Sugar, 200 g Golden Syrup
Place the oats and chocolate chips in a mixing bowl and pour on the cooled melted butter mixture. Give everything a good stir.
400 g Oats, 100 g White Chocolate Chips, 100 g Milk Chocolate Chips
Press the mixture into the tin and bake for 30 minutes. The flapjack will be quite soft when you take it out of the oven but will harden up on cooling.
Whilst the flapjack is still warm, use a sharp knife to score it into squares. Leave to cool fully.
Drizzle the melted white and dark chocolate over the top and leave to set.
50 g White Chocolate, 50 g Dark Chocolate
Use a sharp knife to cut the flapjack into squares.