Line a 9-inch square pan with parchment paper.
Spray with cooking spray. Set aside.
In the bowl of a stand mixer, beat egg white to medium peaks. Set aside.
Combine sugar, corn syrup, and water in a 6 quart pot.
Bring to a boil, occasionally brushing down sides with a pastry brush dipped in warm water.
Continue to cook until candy reaches 270℉/132℃.
Turn the mixer back on and carefully stream sugar mixture into egg whites.
Beat for 3 minutes.
Beat in butter and vanilla.
Pour immediately into prepared pan.
Allow to cool at room temperature.
Cover with plastic wrap and refrigerate overnight.