Line a rimmed cookie sheet (also known as a jelly roll pan) with parchment paper.
Align crackers side by side in a single layer along baking sheet then set aside.
In a medium saucepan combine the butter and brown sugar and bring mixture to a boil over medium heat, stirring frequently. Once it reaches a boil stop stirring and allow to boil 3 minutes.
Remove from heat, stir in the vanilla then immediately and carefully pour mixture over crackers in an even layer. You will need to spread it out evenly using the back of spoon.
Place in the oven and bake 5 to 6 minutes until bubbly.
Remove from the oven and sprinkle the top evenly with the chocolate chips.
Let rest 5 minutes then using the back of a spoon spread the melted chocolate into a smooth layer. Sprinkle the pecans over the top evenly.
Move to the freezer (or outside if you live where I live!) and allow to chill 20 minutes or until chocolate has set.
Remove from freezer and break or cut into pieces. Store in an airtight container.
Notes
Nutritional values may vary.Servings depend on how big or small you crack the pieces into.