Line a 18 x 28cm slice tin with baking paper and set aside until needed.
Place the butter, brown sugar and honey into a small saucepan and cook over a low heat for 10 minutes or until the mixture thickens.
In the meantime, place the oats, puffed rice and cinnamon into a large bowl and gently stir to combine.
Add the vanilla extract to the cooked honey mixture and stir well before adding to the bowl with the dry ingredients and stirring through until well combined.
Pour the mixture into your prepared slice tin and use the back of a spoon to push it firmly down to flatten the surface.
Sprinkle the chocolate chips over the top of the slice and gently press them into the slice.
Transfer to the fridge to chill for six hours (preferably overnight) before cutting into bars.