First of all, you need to make a caramel. Don’t leave the cooker while you’re doing this and don’t have any small children or pets nearby. Place the sugar and 2 tablespoons water in a heavy saucepan over a medium heat, allowing the sugar to dissolve. You can swirl the pan but don’t stir or the sugar can crystallise. Once the sugar has melted, continue to cook on medium heat until you have a golden caramel. Once the colour has changed, Immediately
remove from the heat and whisk in the butter until combined. The mixture may “whoosh” up, so be careful.
Add the Baileys, Guinness reduction and salt (be very careful – the caramel may splatter). Cook over moderately low heat, stirring, until caramel is smooth.
Set the caramel sauce aside for about 10-15 minutes to cool a little. Whisk in the icing sugar, stirring well to dissolve, then stir in the double cream. Stand for about 10-15 minutes before pouring about a third of the glaze over the brownies (keep a little for serving later) in the fridge for about 30 minutes or longer, if needed. When you’re ready to serve the brownies, cut into bars.