Preheat the oven to 180°C (160 fan, Gas 4) and line a 20cm (8") Square baking tin with baking paper.
In a large saucepan melt together the butter, golden syrup, and sugars over a low heat.
225 g Butter, 100 g Demerara Sugar, 100 g Light Brown Sugar, 5 tablespoon Golden Syrup
Take the pan off the heat and stir in the vanilla extract, oats and raspberries.
1 teaspoon Vanilla Extract, 360 g Oats, 125 g Raspberries
Press the mixture into a greased and lined 20cm square (8 inch) baking tin.
Bake in the oven for 22-25 minutes until golden on top.
Immediately score the top of the flapjacks with a sharp knife, then leave them to cool in the tin for at least 1 hour (I often leave them overnight) before cutting them into bars.