Preheat your oven to 180°C/350°F/Gas 4. Put the butter and sugar in a pan and melt over a gentle heat.
Remove from the heat and stir in the the oats and golden syrup. Mix well.
Grease and line an 8x10" (200x250cm) baking tin. Add the mixture and press in to the tin, smoothing out. Bake for 30 minutes. It will feel soft when removed form the oven, but will harden on cooling.
Cut into slices while warm and drizzle with melted chocolate.
Video
Notes
Try not to over heat the butter, otherwise it will split like it has in our photo. However it won't make much of a difference to the final taste and texture.
Add a pinch of salt to intensify the flavour. However we left this out as we were making it for kids to eat.
Make these gluten free by by using gluten free oats
Leave them to cool completely before cutting. This allows them to firm up and keep their shape.