Preheat oven to 300°F. Spray a rimmed baking sheet with cooking spray.
In a bowl, combine cereals, pretzels, crackers, and peanuts.
In another bowl, whisk egg whites until foamy. Whisk in Splenda Stevia Sweetener, Worcestershire sauce, and cayenne. Pour over cereal mixture, tossing to coat.
Spread mixture in a single layer on prepared baking sheet.
Bake for 20–25 minutes, stirring every 10 minutes. Cool completely.