For frosting, combine scream and chocolate in a saucepan over low-medium heat and cook, stirring constantly, until cream and chocolate is smoothly combined. Don’t boil the mixture, but it should be steaming hot.
Remove from heat and let cool in the fridge, stirring occasionally to keep it smooth, for 90-120 minutes.
For cakes, combine stout and butter in a sauce pan and put over low-medium heat until butter is melted.
Then whisk in cocoa powder. It’s a lot of cocoa powder, so work slowly and make sure the mixture is nice and smooth. Remove from heat and let cool.