In a medium saucepan, combine the granulated sugar, corn syrup, and water. Bring the mixture to a boil over medium heat, stirring until the sugar dissolves.
Once boiling, stop stirring and let it cook until it reaches the soft-ball stage (approximately 240°F or 115°C), which can be tested by dropping a small amount into cold water; it should form a soft ball.
While the syrup is cooking, beat the egg whites and salt in a large mixing bowl until stiff peaks form.
Once the syrup reaches the right temperature, remove it from the heat and let it cool for a minute without stirring.
Slowly pour the hot syrup into the egg whites in a steady stream while continuously beating with an electric mixer on medium speed. Be careful not to pour it directly onto the beaters.
Continue to beat the mixture until it thickens and starts to lose its gloss (about 5–10 minutes). Stir in the vanilla extract and chopped nuts.
Spoon the fluffy mixture onto parchment paper or a silicone baking mat, spreading into small mounds. You can shape them with a buttered spoon for a more uniform look.
Allow the candies to cool completely and dry, ideally for a few hours or overnight, until firm before serving.