Line a cookie sheet with parchment or silpat. Set aside.

In a medium-small sized saucepan attach a candy thermometer. Add walnuts, both sugar, and water. Stir until well combined. Add butter.

Cook over medium heat, stirring constantly, until mixture reaches 285-290 degrees, being careful not to burn. Remove from heat and stir in vanilla. If butter separates continue to stir until recombined.

Working quickly spread nuts on lined baking sheet. Use 2 forks to separate nuts. Allow to cool until hardened.