Line a 6.5 liter / 6 quart slow cooker with either a liner or baking parchment. I don't have any liners so I used baking parchment. Lining it will make it easer to take the cake out and store it and to clean your slow cooker but it is not an essential step.
In a small bowl add in the flour, sugar, cocoa powder, baking powder and salt, whisk till fully combined.
Add in the milk, oil and vanilla and stir everything together until just combined.
Pour the batter into your slow cooker and spread it out into a thin layer.
Sprinkle the chocolate chips over the top so they are evenly distributed.
Wipe your mixing bowl out with a paper towel or use a clean bowl and add in the sugar and cocoa powder for your hot fudge sauce and give it a little mix.
Carefully pour in the boiling water and mix until everything is combined.
Very carefully pour this liquid over your cake batter and whatever you do resist the urge to stir! Let the liquid sit on top of the cake batter.
Place the lid on your slow cooker and pop it on high and go and relax.
Check your cake after one hour for doneness, all slow cookers vary and yours may take less time then mine did. The original recipe called for 1 and 1/2 hours but mine took a little over 2 hours to bake through.
Poke it with a pick and if it comes out clean then you are good to go.
Turn your slow cooker off, take the ceramic dish out and place to one side for 10 minutes to cool down a little before serving.
Serve with vegan cream, vegan ice cream or a little powdered sugar.
Stored in an airtight container in the fridge this cake will last up to 5 days. The sauce will be absorbed into the cake by day 2. Still tastes great.
Pop it in the microwave for 60 seconds to warm it up slightly.