Bring coconut milk to a simmer in a medium saucepan. Meanwhile, line a loaf pan with foil or baking paper.

Remove from the heat and add the chocolate. Stand for a few minutes so the chocolate melts.

Stir in the peanut butter, vanilla and oat bran, if using.

Transfer fudge mixture to the prepared tin and refrigerate for a few hours, or until set.

Chop into small squares.