Method

1. Preheat the oven to 180℃ fan, and line a 8 x 8 inch square / loose base tin with grease proof paper.  Allow the paper to hang over the edges of the tin, this makes it easier for removing the bars when ready.
2. Break the bourbons in half, and use them to line the base of the tin, making sure the bourbon logo is facing downwards (watch the video for visual reference here). 
3. Sift the cocoa powder and flour together in a medium bowl.
4. Fill a small saucepan 1/4 full with water and place on the hob over medium heat. Add the dairy-free chocolate and butter into a heat proof bowl. Place the bowl over the pan, creating a bain-marie. Allow the chocolate and butter to melt together, stirring with a heat proof spatula. Remove from the heat and allow to cool for a few minutes while you make prepare the aquafaba.
5. Add the aquafaba and sugar into a medium sized mixing bowl and whip up on high speed for around 5 minutes until thick and glossy. I use a stand mixer with balloon whisk attachment. A electric hand whisk will work great too. Whip on high speed, the aquafaba mixture should be thick enough that when it drips into the bowl, the mixture should ribbon off the mixer.
6. Pour the chocolate and butter mixture over the aquafaba, and carefully fold together with a spatula. Make sure to be very gentle with this step as you want to keep as much air in the mixture as possible.
7. Once combined, sift in the flour and cocoa powder. Again, fold this in with a spatula until a rich and thick brownie batter forms.
8. Break up a few bourbon biscuits and sprinkle into the batter, fold to combine.
9. Pour the brownie batter into the lined tin and level off with an off-set spatula.
10. Place the tin into the middle of the oven and bake for 30-35 minutes. If you want a more fudgey brownie, you may want to underbake by 5 minutes!
11. Once baked, remove the tin from the oven and allow to cool fully on a wire rack. TIP: Keep the brownie in the tin while it’s cooling. This will help it keeps it’s shape and will also lock in some of the moisture, which will help with the chewy texture.
12. Use a sharp knife to cut the brownies into little bars. Cut the brownies so each has a bourbon biscuit on top.
13. Serve and enjoy!