In a heavy large pressure cooker, add salt and spread it out.

Remove gasket and whistle from the lid and cover the cooker.

Heat on medium flame for 15 minutes.

In a bowl mix together flour, sugar, baking soda, cocoa powder and whisk until well incorporated.

Add milk, curd, oil, vanilla, food colour and vinegar and whisk to form a smooth batter.

Pour in a greased and lined cake tin and place the cake tin carefully inside the cooker. Place some rings so that the cake tin doesn't touch the salt.

Cover and set the flame to low.

Bake for 30 - 40 minutes until a tooth pick inserted comes out clean.

Remove from the cooker and cool on wire rack for 5 minutes.

Then flip the cake onto the wire rack and allow it to cool completely before decorating it with frosting of your choice.