Grease and line a standard sized (approximately) 17X28cm rectangular baking tray with baking paper, allowing the edges to overhang.
Place the rolled oats, rice bubbles and almonds into a large bowl. Mix to combine.
In a small saucepan, bring the peanut butter, honey, brown sugar, vanilla essence and butter to a boil (stirring continuously).
Reduce the heat and simmer (while stirring) for 2 minutes or until the sauce has thickened.
Pour the sauce over the dry ingredients and mix really well – so that all of the dry ingredients are completely covered.
Spoon the mixture into the prepared tray and press down very firmly with the back of a spoon.
Place the tray into the fridge for 2 hours.
Take out and cut into long bars.
Place the bars into an airtight container and store in the fridge for up to 5 days.