Spray the interior of the slow cooker with cooking spray.
In a medium bowl, mix together the granulated sugar, brown sugar and cinnamon. Set aside.
In a separate large bowl, add the egg white and vanilla. Whisk until frothy. Add the almonds and stir, thoroughly coating the almonds with the egg white mixture.
Add the cinnamon sugar mixture to the bowl of coated almonds and stir to completely combine.
Pour the mixture into the slow cooker. Cover and turn the slow cooker on low for 4 hours.
Stir every 20 minutes. At the last hour, add the water and stir to thoroughly combine. This step gives the cinnamon sugar almonds their crunchy coating.
Lay out a large sheet of parchment paper. Once the slow cooker is done, pour the cinnamon sugar almonds on to the parchment paper to cool. Be sure to separate the almonds.
Enjoy!