Martha makes a sweet, crunchy pistachio brittle for Passover.
Line a baking sheet with a nonstick baking mat; set aside. In a medium bowl, mix together farfel, pistachios, and cayenne pepper; set aside.
Place sugar and salt in a medium saucepan; add 1/3 cup water and mix to thoroughly dampen. Place saucepan over medium-high heat and cook until medium amber in color, swirling and brushing down sides of saucepan with a pastry brush dipped in water to prevent crystallization. Carefully add butter (mixture will bubble up). Stir until melted and well combined.
Working quickly, add farfel mixture and stir to combine. Pour mixture onto prepared baking sheet; using an offset spatula, spread into a very thin layer. Let cool completely. Break brittle into pieces before serving.