Spray your slow cooker with non-stick spray and set aside.
In a large bowl, add the sugar, brown sugar, cinnamon, and salt. Whisk together.
In another large bowl, add the egg white and vanilla and whisk until frothy.
Pour the almonds in the egg mixture and toss them around to coat thoroughly.
Pour the coated almonds into the sugar mixture and toss to coat.
Pour the entire mixture into the slow cooker and turn to low.
Cook for 3-3.5 hours, stirring every 20 minutes. It will look like not much is happening for a long time but your house will smell good!
After 3 hours, pour in 2 Tablespoons of water and stir well. If they look dry, add another 1 Tablespoon of water. This is going to make the crunchy coating and things will start looking right.
Replace cover & cook for another 20-30 minutes.
Meanwhile, line a baking sheet with parchment paper.
When done, pour the almonds onto the prepared baking sheet and separate any that stuck together. Let them cool slightly to harden then enjoy!