Pre-Heat oven to 325 Degrees C.
Line an 8x8 inch square pan with foil and spray with oil.
Place the vegan butter and chocolate in a small sauce pan and melt over low heat. Leave to cool.
In a large bowl mix together the coconut sugar, cocoa powder and salt.
Pour in the chocolate mixture into the dry ingredients.
Mix in the eggs and vanilla paste until it is nice and smooth with no lumps.
Add in the cassava flour and fold in until incorporated in the batter.
Pour in the batter in the lined tin and bake for 25 minutes.
Leave to completly cool in the tin, then lift out and cut into 16 squares.