Step 1: In a medium-sized heavy-bottomed saucepan, combine the granulated sugar, light corn syrup, and water. Stir these ingredients over medium heat until the sugar has completely dissolved. It's important not to rush this step, as dissolved sugar is crucial for a smooth taffy base. Keep stirring gently to prevent any sugar crystals from forming on the sides of the pan.
Step 2: Once the sugar is dissolved, stop stirring. Insert a candy thermometer, ensuring it doesn't touch the bottom of the pan. Bring the mixture to a boil and cook until it reaches precisely 260°F (127°C), which is the hard-ball stage. This temperature is vital for the taffy's final texture. Monitor the thermometer closely, as candy can quickly overcook. As soon as it hits 260°F, immediately remove the saucepan from the heat.
Step 3: With the saucepan off the heat, quickly stir in the packet of Kool-Aid, unsalted butter, vanilla extract, and salt. Stir vigorously until all ingredients are thoroughly incorporated and the butter has melted completely. The Kool-Aid will infuse your taffy with vibrant color and fruity flavor, while the butter adds richness and the salt balances the sweetness.
Step 4: Carefully pour the hot taffy mixture onto a generously greased baking sheet or a silicone mat. Spread it out gently with a greased spatula. Allow the candy to cool slightly for about 5 to 7 minutes. It needs to be cool enough to handle safely but still warm and pliable for stretching. If it cools too much, it will become brittle and difficult to work with.
Step 5: Generously butter your hands to prevent sticking. Begin to pull the edges of the taffy inwards, folding it over itself. Continue stretching and folding the taffy for 10-15 minutes. As you work it, the taffy will become opaque, lighter in color, and develop its characteristic chewy texture. The more you pull, the chewier and shinier it will become. This process incorporates air, giving taffy its unique appeal.
Step 6: Once the taffy is firm, shiny, and sufficiently stretched, it's time to shape it. Roll the taffy into a long rope, about 1/2 inch in thickness. The length will depend on how many pieces you want to make. Using a sharp, buttered knife or kitchen shears, cut the rope into bite-sized pieces, typically 1 to 1.5 inches long.
Step 7: To keep your beautiful homemade taffy from sticking together, wrap each individual piece in small squares of wax paper or parchment paper. Twist the ends of the paper to seal. Allow the wrapped taffy to cool completely at room temperature. Once cooled, it's ready to enjoy! This is also a great way to store them for later enjoyment.