Preheat the oven to 400F for at least 20 minutes prior to baking.
2
In a saucepan, combine the butter, sugar, salt, lemon rind, and water and bring to a boil. Remove from the heat.
3
Add the flour all at once to the saucepan and stir to combine. At first, stir carefully to keep the flour in the pan, then vigorously to ensure it is completely combined.
4
Return to a medium high flame and cook 3 - 4 minutes or until the batter clings and is glossy. Remove from the heat.
5
Add the vanilla and rum and allow the mixture to cool (in the pan).
6
Add the eggs one at a time with a wooden spoon.Beat vigorously and combine completely before adding the next egg. Don't worry - the batter will break every time, but keep working it until it comes back together and gets sticky again. This may take around 15 minutes.
7
If making chouquettes, drop quarter-size balls onto a parchment paper lined baking sheet and sprinkle generously with Swedish pearl sugar. Bake 5 - 20 minutes (these need to be totally brown when you remove them from the oven or they will collapse from the moisture).