Here's the recipe we used from exploratorium.edu:
2 cups sugar
2 tablespoons cornstarch
1 cup light corn syrup
2 teaspoons glycerin (optional)
3/4 cup water
2 tablespoons butter
1 teaspoon salt
1/4 to 1 teaspoon flavoring (such as vanilla, lemon, maple, or mint)--we used a whole teaspoon.
3 drops food coloring (optional)--we didn't bother with it.
a large (3- to 4-quart) saucepan
a wooden spoon
a candy thermometer
a pastry brush
waxed paper or plastic wrap
a marble slab or cookie sheet
greased scissors or butter knife
1. Mix together sugar and cornstarch in the saucepan.
2. Use a wooden spoon to stir in the corn syrup, glycerin, water, butter, and salt. Place the saucepan over medium heat and stir until the sugar dissolves.
3. Continue stirring until mixture begins to boil, then let cook, undisturbed, until it reaches about 270° F or the soft-crack stage. Wash down the sides of the pan with a pastry brush dipped in warm water while the syrup cooks.
4. Remove the saucepan from the heat and add food coloring and flavoring. Stir gently, then pour onto a greased marble slab or into a shallow greased cookie sheet to cool.
5. When the taffy is cool enough to handle, grease your hands with oil or butter and pull the taffy until it's light in color and has a satiny gloss. You can have a friend help with this step, which should take about 10 minutes.
6. Roll the pulled taffy into a long rope, about 1/2 inch in diameter, and cut it with greased scissors or a butter knife into 1-inch-long pieces. Let the pieces sit for about half an hour before wrapping them in wax paper or plastic wrap and twisting the ends of the wrapper.
The recipe says that pulling the taffy will take about 10 minutes, but it was over half an hour before it got anywhere NEAR the right texture for us. Then again, we're not sure we were doing it quite right... ah, well. It ended up yummy!