Line with parchment paper in the slow cooker bowl and spray the parchment paper.

In a medium bowl, add the flour, 100g sugar, cocoa powder, baking powder and whisk to combine. Add the milk, oil, vanilla, and stir until just combined.

Pour the batter in the slow cooker into a smooth, even, flat layer. Scatter the chocolate chips.

In a second bowl, combine the rest of the sugar with 3 tbsp. cocoa powder. Whisk in the boiling water until smooth.

Carefully pour the hot cocoa-water mixture over the batter in the slow cooker. Do not stir. This mixture turns into hot fudge while the cake bakes; do not stir.

Cover and cook on high for about 1 1/2 to 2 hours, or until a toothpick inserted into the centre of the cake comes out clean.

Start checking at just over one hour to ensure you don’t overbake.

Remove the slow cooker bowl from the slow cooker and set aside for 5 minutes before serving while warm with whipped cream / or ice cream.

If you let it cool off the sauce will absorb into the cake.