Line bottom and sides of a small jelly roll pan (~8.5" x ~11") with parchment paper or wax paper.

In a medium saucepan over medium heat, melt butter. Stir in sugar, vanilla extract, and salt. Continue stirring frequently until the mixture reaches 280 to 290 degrees F (the mixture will be amber in color and have a nutty smell).

Pour mixture into prepared baking pan and spread evenly with a spatula. Be careful not to touch the liquid as it will burn you!

Sprinkle chocolate chips evenly over top of mixture. Let chocolate sit and melt for 1-2 minutes, then use spatula to spread chocolate evenly over top.

Sprinkle crushed pecans evenly over chocolate.

Transfer pan to refrigerator until toffee has firmed, about 2 hours. Once firm, break into pieces.