Pulse the oats in a food processor or blender for 3 seconds at a time until the oats are broken up. Don't let it turn into flour. You still want to see some flakes.
Melt the butter on the stove and, once melted, whisk in the golden syrup, brown sugar, and salt. Heat just until the sugar is dissolved.
Pour the oats into a large bowl with any add-ins that you'd like - a handful or two of dried fruit, nuts, or seeds. Pour the melted mixture into the oats and stir until combined.
Pour the mixture into a greased 8x8" (20x20cm) pan. Press it down until it is compact and flat.
Bake in a 325℉ / 160℃ pre-heated oven for 25-30 minutes.
If you want a layer of chocolate, sprinkle the hot surface generously with chocolate chips. Pop it back in the oven for 2 minutes. Remove it and spread the melted chocolate over the surface with an offset spatula. To set the chocolate quickly, let the bars cool in the fridge. Don't slice into these until they're at least a room temperature and the chocolate is set.
