In a saucepan, melt the butter and add the sugar and golden syrup.
Keep on low heat until the sugar dissolves (do not boil and stir constantly).
Remove from the heat and add the oats, mix until well combined.
Roll the mixture to around 3 cm thick on a greased baking tray.
Bake on a previously pre-heated oven at 180°C for 20 minutes or until golden brown.
Allow to cool down completely and then cut into squares.