Combine sugar, corn starch, salt, butter, corn syrup and water in medium saucepan.
Heat on medium heat, stirring, until mixture comes to a boil.
Add candy thermometer to pan and cook, without stirring, until mixture reaches 250-253 degrees (see notes about cooking temp).
Pull pan off of heat and add 3-4 drops of food coloring and flavoring oil. Stir.
Imediately pour mixture onto buttered baking sheet. Allow to cool until you can handle it. Mixture should be warm when you begin to pull the taffy, not hot.
Spread a small amount of butter onto your hands, or onto your food gloves (I like using gloves) then remove taffy from baking sheet, form into a ball and begin to pull taffy.
Taffy will start out looking glassy and darker in color, but will change to a satin texture and lighter in color.
It will change from soft and stringy to stiff and smooth.
This can take anywhere from 5-15 minutes.
Roll taffy into a rope.
Cut taffy, with buttered scissors, into bite sized pieces.
Wrap taffy in small squares of wax paper.
This recipe makes 30-40 pieces of taffy, depending on the size you cut the pieces.
Video
Notes
You can use salted or unsalted butter.
Flavoring oils are much stronger than extracts. If using flavoring oils use ½ teaspoon (½ a dram). If using extracts use 1 teaspoon.
The perfect taffy temperature can fluctuate depending on altitude. You'll find suggestions from 246 degrees all the way up to 256 degrees. I've made many batches of taffy and have found 252 to be the right temp for my taffy. I live close to sea level. Higher altitudes may want to reduce the temp to 246. I believe the rule is to subtract 2 degrees for every 1000 feet above sea level.
If your taffy hardens quickly and looks like hard candy/glass you cooked it too long. If the taffy is runny and a slimy mess it wasn't cooked long enough. A good candy thermometer is essential to ensure the proper temp.
If taffy is slightly sticky after cutting it into pieces, let it stand 15-20 minutes before wrapping. This will allow it to dry on the ends and it won't stick to the wax paper.