Preheat the oven to 350 and line a 8 - 9 inch square brownie pan with baking parchment.
Put the sugar, chocolate, oil and the chocolate soy milk. Into a small saucepan. Heat until the chocolate is melted.
Add the flour and the cocoa and stir.
Pour the mixture into your pre-lined baking tin, spread it around a bit (press it into the corners if it's quite thick already) and bake about 15 minutes, or until a toothpick comes out clean.
Cool the brownies completely, then refrigerate for a couple of hours before cutting. Store in the fridge.