1. Prepare the Crust:

1. Line a baking sheet with parchment paper and set aside.
2. In a medium saucepan over medium heat, combine granulated sugar, brown sugar, and evaporated milk. Stir until sugars dissolve.
3. Bring mixture to a boil, then reduce heat to medium-low. Cook, stirring occasionally, until mixture reaches 240°F (soft-ball stage) on a candy thermometer.
4. Remove from heat and stir in butter, vanilla extract, and pecans. Stir vigorously until mixture thickens and becomes creamy.
5. Drop spoonfuls of the mixture onto the prepared baking sheet, spacing them apart. Let cool completely until firm.