Butter a cookie sheet and line it with parchment paper. butter the parchment and set the sheet aside. 

Wash and thoroughly dry the apples. Remove stems and turn the apples upside down. Insert a craft stick into base of each apple, pushing 2/3 of the way through. 

Combine sugar, corn syrup, and water in a heavy medium saucepan. Stir over low heat until the sugar is completely dissolved and the syrup comes to a boil. "Wash" down the sides of the pan with a wet pastry brush to remove any sugar crystals that may have formed. 

Clip a candy thermometer to the inside of the pan, making certain that it does not touch the bottom and cook the syrup, without stirring, until it reaches 300 degrees F. (some recipes call for cooking to 310 degrees, which is a little beyond the hard crack stage, but your candy will have a slight caramel taste to it.) Remove pan from heat and stir in the food coloring. Let the syrup sit until it stops bubbling and add the cinnamon oil. 

Tilt the pan to create a deep pool of sugar syrup. Dip one apple into the syrup, turning to cover it completely. Allow any excess syrup to drip back into the pan, then place the apple on the prepared cookie sheet. Repeat with remaining apples. Allow the coated apples to cool completely, at room temperature, about 1 hour. Peel off of parchment and cut to serve. 

Store cooled apples loosely wrapped in wax paper at room temperature for up to 2 days.