Grease and line an 18 cm (7 inch) square deep cake tin.
Beat together the sunflower spread, eggs and sugar. Stir in the flour and cocoa, then add the chocolate and chocolate extract. Stir in 1 teaspoon boiling water and a pinch of salt.
Transfer the mixture to the prepared tin and bake in a preheated oven, 190°C (375°F), Gas Mark 5, for 30 minutes or until a skewer comes out clean when inserted in the centre. Leave to cool in the tin then cut into 9 squares. Dust with a little cocoa powder to serve.