1 cup unsalted butter, softened
2 cups white sugar
1 egg
1 tablespoon water
1/8 teaspoon salt
Line a 9x13 inch baking pan with foil.
In large bowl, beat butter until smooth and pale. Gradually add sugar and water; blend until smooth. Whisk egg and salt 1/2 cup at a time, then gently stir in sugar mixture. Continue to blend and pour into prepared pan.
Bake 25 to 30 minutes in the preheated oven, until centers are set. Set aside, and cool before serving.