I do this too. I used to add it to the milk before steaming but that had obvious drawbacks.

Afaik this is how to make a Cuban espresso. I was taught to mix the sugar with the first few drops inside the moka pot, but I’m sure it would do the same thing mixed in a glass

We used to pack brown sugar right on top of the espresso before pulling a double shot and running it into about an oz of half and half. Delicious and easy to drink immediately.

Salt?

I immediately thought this was salt. Maybe I’m the monster.