Preheat the oven to 200 C / 180 C fan / Gas 6. Line a 28x16cm (3cm deep) baking tray with greaseproof paper.
Mix the oats and sugar into a large mixing bowl. In a small saucepan over a medium heat, melt the butter and golden syrup. Once the butter has melted, add it to the bowl with the oats and sugar then mix well making sure there are no dry patches. Finally scoop the mixture in the prepared baking tray and press down with the back of a spoon to compact (and squashing it into all the corners).
Bake in the oven for 15 to 20 minutes until golden brown. Once it has cooked take it out the oven and the baking tray and cut into 6x6cm squares. Then let them cool for 10 minutes. Enjoy.