Line a 9x13 cake pan with parchment paper; spread 2 cups of peanuts into an even layer.
In a medium-size pan add butter, sugar, and vanilla. Stir over medium heat until butter has melted. Let come to a simmer.
Simmer for 7-8 minutes, stirring occasionally.
Watch carefully so it doesn’t burn. The mixture gradually turns darker and is still a little separated. When the mixture turns the shade of caramel and flows from the spoon in a ribbon, pour over the peanuts.
Use an off-set spatula to spread mix over the peanuts.
Pour a bag of chocolate chips over the top and let set for 2-3 minutes so chocolate chips melt.
Using off-set spatula, spread melted chocolate over the layer of toffee.
Chop the remaining ¼ cup of peanuts and sprinkle over the top.
Let set for 2 hours until the pan comes to room temperature and then place in fridge until ready to enjoy. Which might be immediately!