Preheat your oven to 350 degrees and spray a 13 x 9 baking pan with non-stick cooking spray. Line the pan with parchment paper, enough so that it hangs over the sides
In a large bowl, combine the flour and salt and set aside.
In a sauce pan, melt your chocolate chips and butter over medium heat.
Continuously stir until smooth and then add in the instant coffee, if you are using it.
Remove from the heat and let sit for 5-10 minutes to cool slightly.
After the 5-10 minutes go by, whisk in the sugar and vanilla.
Add in your eggs, one at a time and then fold into the flour mixture until it just barely comes together.
Take care not to over mix the batter.
Pour your batter into your baking pan and cook for 25-30 minutes.
When done, remove from the oven and set pan on a cooling rack, letting your brownies cool completely (at least 2 hours)
In a large bowl, beat together butter and peanut butter until smooth.
Add in the confectioners sugar, little by little until all is incorporated.
Add vanilla, whipping cream and salt and continue to beat together for another minute.
Carefully remove your brownies from their pan using the parchment paper to lift them up so that your brownies are one solid sheet.
Spread the peanut butter filling over the cooled brownies, creating a thick layer.
In the same saucepan you used earlier, combine your chocolate chips, peanut butter and instant coffee, if you are using.
Continuously stir until everything is melted and smooth.
Again, allow your mixture to cool for 5-10 minutes and then pour the topping over the peanut butter layer and smoother evenly, pushing the chocolate out to each edge of the brownie.
Chill in the refrigerator for at least one hour.