Line a large rimmed baking sheet with parchment paper.
In a medium heavy-bottom saucepan over medium heat, combine the butter and sugar. Cook, stirring consistently until the candy reaches 285°F on a candy thermometer, achieving a dark amber color.
Pour the candy mixture onto the lined baking sheet. While still hot, top with chocolate chips and let it rest for 1-2 minutes to soften before spreading into an even layer.
Sprinkle with pecans and gently press them into the melted chocolate.
Let it sit for about 1 hour, or until set.
Break into pieces to serve.
Store pieces in an airtight container at room temperature for up to a week.