Liberally grease a baking pan with cooking spray.

Combine the sugar, corn syrup, salt and water in a large saucepan.

Heat to 234 to 240F/112 to 116C using a candy thermometer.

(alternatively, drop a small amount of the syrup into cold water, it should form a soft ball. Remove the ball from the water and place it on a flat surface. If the ball flattens, it is ready)

When it is at the correct temperature, remove it from the heat.

Using an electric mixer, beat the mixture for 10-12 minutes until it forms stiff peaks.

Gently stir in the vanilla extract.

Pour the mixture into the greased baking pan, and gently spread.

Place in the refrigerator and allow to chill overnight.

Liberally dust the surface with confectioners sugar, loosen the edges, turn out and liberally dust the other side.

Keep dusting with confectioners sugar while cutting and slicing to avoid any sticking.