Peanut Butter Billionaire Brownie

I had been planning this Peanut Butter Billionaire Brownie bad boy for a while.  At first I wanted to make something like Millionaire Shortbread (caramel slice), then I thought ‘why not make it a brownie?’  And then I thought ‘why not change the caramel to peanut butter?’  That’s where I got stuck.  I couldn’t figure out how I was going to make the peanut butter layer, until one day on my drive home from work (where most of my best baking inspiration strikes) it hit me – use the same mixture that I make my Peanut Butter Marshmallow Tart out of.  Genius!  It was on. 

Now, I’ve made this slice three times.  The first time I mucked up and kept forgetting ingredients, the second time I didn’t wait long enough for the middle layer to set before pouring on the chocolate ganache (causing it to mix with the peanut butter).  The third time was perfect.  This slice is also nicknamed ‘fat girl slice’ by Courtenay and I because it is made form such delicious ingredients and I was too impatient to get eating it, causing the stuff up on the second attempt.  Trust me though, this slice is amazing.  Both mine and Simon’s co-workers loved taste testing this one for me!  Follow the instructions (do as I say, not as I do) and you will be rewarded with one rich, moreish treat.  Fudgy brownie, a silky peanut butter marshmallow layer, topped with a smooth band of dark chocolate. Mmmm.

I’ve broken the ingredients and method into the three layers to make it easier to work out what ingredient is being used where.

BROWNIE BASE
Ingredients:
1 ½ cups flour
½ teaspoon salt
½ teaspoon baking powder
1 cup brown sugar
½ cup white sugar
⅓ cup cocoa
125g butter, melted
2 eggs, lightly whisked
1 teaspoon vanilla essence
½ cup milk chocolate bits

Method:
Heat oven to 180°C. Line a 20cm square pan with baking paper. Mix the flour, salt, baking powder, sugars, and cocoa together in a large bowl.  Add in the wet ingredients and mix well to combine.  Stir through the chocolate bits. 
Press the mixture into the lined pan and bake for 30 minutes, or until firm. Cool in the pan for 5 minutes before pouring the peanut butter topping over (make this while the brownie is baking).

PEANUT BUTTER MARSHMALLOW FILLING
Ingredients:
3 tablespoons milk
36 white vanilla marshmallows (normal sized – about half a pack of pascall ones)
¾ cup smooth peanut butter
300ml thickened cream (the stuff that comes in the tub)
½ teaspoon vanilla extract

Method:
Place the milk, marshmallows and peanut butter into a saucepan over a medium / low heat and stir until the marshmallows are melted and the mixture is smooth (take off the heat and mix briskly if it starts to caramelize / or forming toffee-like threads – this means it is burning, so you need to mix the heat out and turn the element down).  Cook, stirring, for a further 5 - 10 minutes until the mixture becomes a thicker, toffee-like texture.  Set aside for 5 minutes to cool.
Beat the thickened cream and vanilla extract using an electric beater until soft peaks form.  Add a quarter of the cream mixture to the peanut butter mixture, stirring to combine.  Fold through the remaining cream until combined.  Spread the peanut butter mixture over the top of the prepared biscuit base.  Place the brownie / peanut butter slice in the refrigerator for 4 hours, or until the peanut butter layer has set before moving on to making the chocolate ganache layer.

CHOCOLATE GANACHE TOPPING
Ingredients:
300ml cream
300g dark chocolate, broken into small chunks
¼ cup salted roasted peanuts, chopped

Method:
Pour the cream into a saucepan and place over a medium heat.  When the cream is close to boiling (tiny bubbles will be visible around the edges of the pot) remove from the heat and add in the chocolate.  Stir constantly until the chocolate has melted and the mixture is smooth.  Leave aside to cool down.
When the chocolate mixture is luke-warm, pour it over the top of the peanut butter marshmallow layer.  Sprinkle the top of the chocolate ganache with the chopped peanuts.
Refrigerate until the chocolate layer is set (I left mine over night) before cutting into squares and serving.