The reason for pouring the cream onto the back of the spoon is to "float" the top layer. The cream's momentum is slowed by being drizzled over the back of the spoon so it does not penetrate the beverage deeply. This technique is used when making drinks that have separate distinguishable layers, such as the white cream floating on the top of the dark Kahlua like a cloud. Excellent video. Really enjoyed it, and coffee liqueur is a happy subject.
I like how you emphasize the ultimate goal to just make a cocktail that you like the way you like it at home. And yea, I agree, if you're coming to my house and I make a cocktail for you from my curated bar, I would be really mad at you if you make a comment on how I grab the ice. But if this is supposed to teach people working at a bar, yea, you probably wouldn't touch the ice cubes.
Pouring it on the back of the spoon helps keep the liquid from combining together which helps you get that layered esthetic that you want for a shooter.
I actually made a white Russian with my girlfriends French vanilla coffee creamer when i ran out of heavy cream one night. It's my new favorite! The best cocktail recipes are discovered when you're hammered.
I'm neither white nor a man discuss. Sorry I'm a fan of balance. Like three or four of you have good souls and I hate to give a few good people bad news. Sincerely, Miss J