In a large saucepan heat the honey and butter, this will foam and will begin to darken in colour. As you heat the butter and honey will form a caramel, you will know it's ready when you can draw a spatula through the mixture and you will be able to briefly form a channel.
While the caramel is boiling, combine all the nuts, seeds, and puffed rice together in a mixing bowl. This is also a good time to line a loaf tin with baking paper.
Remove the caramel from the heat, stir through the vanilla and then add the nuts and seeds.
While the energy bar mix is still hot, press into the bottom of the baking paper-lined loaf tin.
Allow the energy bar mix to cool, you can do this on the bench or in the fridge, remove from the loaf tin and slice into bars.
Store in an airtight container, if you live in a hot climate I would recommend storing the energy bars in the refrigerator. If you store them in the fridge they will be crunchy, if they are stored in a warm environment they will still be delicious but they will be a bit softer and chewier.