The first step is adding sugar, corn syrup, and water to a heavy-bottomed pot over medium-high heat.
Second, boil the mixture, stirring constantly until the sugar is dissolved.
Third, once the sugar and water have come to a boil, stop stirring and let the liquid reach a temperature of 240 degrees F.
Then, when the sugar water mixture has reached 240 degrees, stir in the almonds, cinnamon, salt, and butter.
Next, stir the mixture to prevent burning and cook until it reaches 300 degrees F. It will begin to turn golden brown.
Once the mixture has reached 300 degrees F., please remove it from the heat and stir in the baking soda and vanilla.
Immediately pour half of the mixture in a thin layer onto a parchment paper-lined baking sheet and the other half onto another.
Let the brittle cool completely for about an hour.
Finally, break the brittle into pieces and enjoy!