In a microwave-safe bowl, add in the 10 ounces of peanut butter chips and heavy cream. Microwave for 1 minutes and stir until the cream and peanut butter chips come together and are completely smooth.
Place in the fridge to chill. If the ganache becomes hard, let it come up to room temperature before whipping it.
Whip the ganache until it becomes fluffy and light in color. It will only take 1 - 2 minutes.
Cake
Preheat oven to 375 degrees. Line a 15x10x1 inch pan jelly roll pan with a piece of parchment paper. Spray the parchment paper with non-stick cooking spray. Dump ¼ cup of all-purpose flour on the parchment paper and tap it on the sides to spread the flour to the edges. Tap out any excess into the garbage.
In a large mixing bowl, add in the 1 cup of flour, baking powder, cinnamon and salt. Whisk until combined. Set aside.
In a separate large mixing bowl, add in the 3 eggs and both granulated and brown sugar. Beat on high for 5 minutes until the eggs double in volume and become very thick and pale.
Add in the mashed bananas, vegetable oil and vanilla. Beat on medium to combine.
Dump the flour mixture into the wet mixture. Stir in with a spatula.
Pour the batter into the prepared jelly roll pan. Spread the batter to all the edges and evenly.
Place in the oven and bake for 13 - 14 minutes or until the edges are golden brown and when you press the cake in the center of the pan it pops back up. You can also use a toothpick and make sure it comes out clean.
Place another piece of parchment paper at least the length of the jelly roll pan on a clean work surface.
Spread the ¼ cup of powdered sugar on the parchment paper.
Flip the hot cake onto the powdered sugar covered parchment paper. Line it up so it's all on the parchment paper.
Peel the piece of parchment paper off that was used to bake the cake with.
Roll the cake up, using the parchment paper that's coated with powdered sugar to prevent the cake from sticking together. Let cool completely.
Once the cake is completely cooled, unroll it. Spread the whipped peanut butter ganache evenly on the inside of the cake. Roll the cake back up. Cut off the rough edges.
Wrap the banana roll cake in plastic wrap. Place in the fridge at least 1 - 2 hours to set.
Garnish
Place the chilled cake on a cooling wrap with a piece of parchment paper underneath the rack.
In a microwave-safe bowl, add in the 1 cup of peanut butter chips and ¼ cup of heavy cream. Microwave for 1 minute and stir until combined. It will become thick and creamy.
Pour the ganache over top of the chilled cake. Using a knife, help spread the ganache down the sides of the cake. Tap the rack to help evenly spread the ganache garnish.
Add the coating chocolate coins in a sandwich bag. Microwave for 45 seconds. Press the chocolate around to mix it. Repeat one more time.
Cut a small corner out of the sandwich bag. Stripe the roll cake with the chocolate. Move your hand from one side to the other while gently pressing the chocolate out.
Move the cake onto a serving dish. Cover with plastic wrap after the chocolate has set. Place in the fridge until it's ready to serve.