Preheat the oven to 425° and position racks in the upper and middle thirds. Lightly butter 2 large baking sheets. In a large saucepan, combine the butter, water and salt and bring to a boil. Remove from the heat. Add the flour and whisk until smooth. Let cool slightly, then, using an electric mixer at medium speed, beat in the eggs 1 at a time, beating thoroughly between additions. Beat in all but 2 tablespoons of the cheese.