Combine the water, sugar, cinnamon and vanilla in a medium saucepan over medium heat.
Bring the mixture to a boil.
Add the almonds and lower the heat to medium-low.
Cook and stir the mixture constantly, about 15 minutes, until all the liquid evaporates and leaves a crystallized coating on the almonds. The time may vary but keep going until the sticky syrup has turned into a sugary powdered consistency. Pay attention as it happens really fast right at the end.
Then quickly remove it from heat and pour the almonds onto the prepared baking sheet.