Prepare a cookie sheet with a silicone mat or by greasing the surface with 2 tablespoons of softened butter.

In a medium saucepan, combine the granulated sugar, salt, corn syrup and water. With a nonstick spatula, stir, just to moisten the sugar and make sure there are no dry spots.

Bring mixture to a boil, over medium heat, this should take about 6 minutes. Reduce the heat to medium low, mixture should be at a gentle steady boil.

Continue to cooking, stirring occasionally with a nonstick spatula, for 10 to 15 minutes, or until the color turns golden brown and the mixture smells toasty. Remove from the heat. Stir in the chopped and whole peanuts, sesame seeds, and salt, immediately followed by the Spicy Chili Crisp (and the optional fish sauce). Quickly stir to distribute, then pour onto the prepared cookie sheet and spread into an even layer as thin as possible. The mixture will harden within seconds, so work quickly. Let cool for 15 minutes then break into pieces.

Brittle will stay fresh in an airtight container for up to 2 weeks!