Line a baking sheet with parchment paper or a silicone mat and set aside.

Combine the sugar and water in a medium saucepan over medium heat. Stir until the sugar dissolves, then stop stirring and let it come to a boil.

Once boiling and slightly thickened (about 2-3 minutes), add the almonds, cinnamon, vanilla, and salt. Stir constantly with a wooden spoon.

Keep stirring as the mixture thickens. The sugar will first look syrupy, then sandy/grainy, then it will melt again and coat the almonds in a shiny caramel glaze. This takes about 8-10 minutes total.

Pour the candied almonds onto the prepared baking sheet and quickly spread them into a single layer using a fork or spoon (work fast — they set quickly!).

Let cool completely, about 10-15 minutes, until the coating is hard and crunchy. Break apart any clusters if desired. Store in an airtight container.