In a saucepan, combine the butter, water, salt and 1 1/2 teaspoons of the granulated sugar; bring to a boil. Remove from the heat. Add the flour and stir with a wooden spoon until combined. Return the saucepan to high heat and cook the dough, stirring until very smooth, 1 minute. Transfer the dough to a bowl. Using a handheld electric mixer, beat in the vanilla, then beat in the eggs, one at a time.