Preheat the oven to 170c. Line a 20 x 10cm brownie tray with baking parchment.
In a small bowl, mix the psyllium husk powder with the water and set aside.
In a medium saucepan over low heat, add the vegan butter and allow to melt completely.
To the bowl of a stand mixer fitted with the paddle attachment, add the cocoa powder and the espresso powder and mix well. Add the melted butter along with the caster sugar and the psyllium egg mixture and beat well.
In a medium bowl, combine the flour and the salt. Add half of the flour mixture to the stand mixer and beat until combined. Add half of the soy milk and beat until combined. Add the remaining flour mixture and beat until combined followed by the remaining soy milk.
Remove the bowl from the stand mixer and add the chocolate chips. With a silicone spatula, mix until the chocolate chips are evenly distributed.
Pour or spoon ⅔ of the brownie batter into the prepared baking tray. Spoon ⅔ of the cooled caramel on top of the batter (it’s best not to spread out the caramel, just allow it to sit in evenly spaced wells across the batter). Top with the remaining third of brownie batter and spread out to just about cover the layers below.
Drizzle the remaining caramel on top and sprinkle with a few pinches of flaky sea salt.
Place in the oven and bake for 35 minutes. The edges should be quite firm but the centre will be quite jiggly when you remove it form the oven.
Place on a cooling rack and allow to cool fully to room temperature. Once cooled, chill in the fridge for at least 2 hours. (I know it’s tempting to eat straight away but I promise you, these taste so much better when chilled).
Once chilled slice into 6 and serve!