First, toast the walnuts by adding them to a dry skillet over medium to low heat until fragrant. About 3-5 minutes. Stir them frequently until they reach a nice golden brown color. Pour toasted walnuts in a small bowl and set aside for now.
In a medium saucepan over medium heat, combine sugar, water, and butter together. Stir frequently until butter and sugar are all melted and the mixture begins to bubble.
Stir in the cinnamon, salt, and vanilla extract. Continue cooking for another 1-2 minutes. Or until mixture has thickened.
Now, pour the toasted walnuts in and stir well until all walnuts are coated evenly.
Pour coated walnuts on baking sheet lined with parchment paper in a single layer, using a spatula to smooth out.
Cool walnuts completely, and then start breaking them apart into bite sized pieces. Store candied walnuts in an airtight container at room temperature for up to 7 days.