Butter a 15x10x1-inch rimmed metal baking sheet and line it with parchment paper, buttering the parchment well, especially the corners and edges. Avoid wax paper—it can’t handle the heat.

In a deep saucepan, mix water, sugar, corn syrup, and red food coloring if using. Heat over medium-high, stirring until the sugar dissolves. Clip a candy thermometer to the side, keeping it from touching the bottom.

Bring to a boil and cook until the temperature reaches 300°F (hard crack stage), about 20 minutes. If it bubbles too close to the rim, lift it briefly from heat and stir.

Slightly over 300°F is better than under, since candy that’s not hot enough won’t harden right.

Once it hits 300°F, remove from heat and quickly stir in the cinnamon oil. Keep your face back—the steam is powerful! Pour the hot mixture onto the prepared pan and spread evenly. Let it cool for about 4 hours.

When firm, dust generously with powdered sugar, flip onto a cutting board, and peel away the parchment.

Break into small pieces using a knife tip or hammer, coat again in powdered sugar, and store in an airtight container.