Pre-heat the oven to 180C/350F/Gas 4.
Grease and flour a 20cm/8in square cake tin with some of the sunflower oil.
In a bowl sift together the flour, salt, cocoa powder and sugar.
Add the oil, soya milk and vanilla extract, and mix carefully together until completely mixed.
Pour into the tin, and bake for about 25 minutes, until the brownies spring back when gently pressed.
Leave to cool for five minutes, then turn out onto a wire rack.