Place the margarine, caster sugar and golden syrup into a food processor and blitz until well combined.
Tip in the oats and pulse until the oats have combined with butter.
Lightly grease a 20 x 20cm baking tin and tip in the flapjack dough. Press the mixture down gently so it evenly covers the tin. Place into the oven and bake for 13 - 15 minutes until golden brown.
Remove from the oven and allow the flapjacks to cool for at least 30 minutes before eating. Cut the tray into 8 - 12 squares once cooled.