This is the toffee that I make and everyone at school loves. Credit to Mom on Timeout. I got the recipe there and changed it a little.
Roughly 1 cup pecans
1 cup butter
1 cup sugar
A pinch salt
A couple handfuls of chocolate chips
Line a baking sheet/pan-type-thingamabob with parchment paper and scatter the pecans around the bottom.
Boil the sugar, butter, and salt over low heat until it reaches 300 F, or 'Hard Crack' on a candy thermometer. If the ingredients start to separate, turn off the heat and stir until they re-combine.
Pour the sugar mixture into your baking sheet/pan-type-thingamabob and let it cool for a bit. Before it's completely cooled, put the chocolate chips on top. Once they melt, spread them around evenly.
Let it cool completely, then eat it all before anyone sees you.