Grease and line a 23 x 34cm/9 x 13 inch baking pan with butter (or cooking spray) and baking/parchment paper and set aside.
In a large saucepan or pot, melt butter over medium heat.
80 g salted butter
Once butter is melted, add marshmallows and stir to coat in butter.
280 g white mini marshmallows
Continue to stir over medium-low heat until marshmallows are melted (I like to use a silicone spatula for this), then mix in peanut butter and vanilla.
130 g peanut butter, 1 teaspoon vanilla essence
Remove from heat, fold in Rice Krispies and mix well to incorporate fully.
5 cups Rice Krispies
Tip mixture into prepared pan, pressing down (with a silicone spatula or clean hands) to compact slightly and create an even layer.
To make the chocolate topping, place chocolate in a small bowl and melt in the microwave in 30-second bursts (mixing with a metal spoon between each burst).
300 g milk chocolate
Once chocolate is melted, mix in extra peanut butter then pour chocolate evenly over base.
130 g peanut butter
Place in the fridge to set.