21/4 c. granulated sugar
1/2 c. light corn syrup
1/4 tsp. kosher salt
3/4 tsp. Red liquid food coloring
1/2 tsp. pure cinnamon oil
1. Lightly grease a large rimmed baking sheet. Stir together sugar, corn syrup, salt, and 1/2 cup water in a large saucepan. Cook over medium-high heat, without stirring, until a candy thermometer reads 310°F, 15 to 20 minutes. Remove from heat. Immediately stir in food coloring and cinnamon oil (stand back from pot when adding oil, as it can sting your eyes and nose). Stir until bubbles are gone from mixture, about 1 minute.
2. Transfer to prepared baking sheet. Let stand at room temperature 1 hour. Crack into pieces and package immediately in cellophane bags or an airtight container. Store at room temperature up to 2 months.