Line a 9×13-inch cake pan with parchment paper. Measure out 2 cups of the roasted sea salt peanuts and spread them in an even layer in the lined pan. Reserve the remaining 1/4 cup peanuts for topping.
In a medium saucepan combine 1 cup real butter, 1 cup sugar, and 1 tsp pure vanilla.
Place the saucepan over medium heat and stir until the butter has melted. Allow the mixture to come to a simmer.
Maintain a gentle simmer and cook for about 7–8 minutes, stirring occasionally and watching carefully so it doesn’t burn. The mixture will darken to a caramel color and may look slightly separated; it should flow from a spoon in a ribbon when ready.
As soon as the mixture reaches that caramel stage, remove the pan from heat and immediately pour the hot toffee evenly over the layer of peanuts in the prepared pan.
Use an offset spatula (or the back of a spoon) to gently spread the toffee so it covers the peanuts evenly.
Immediately pour the entire bag of semi-sweet chocolate chips over the hot toffee. Let the chips sit undisturbed for 2–3 minutes so they soften and begin to melt.
Use the offset spatula to spread the softened/melted chocolate into an even layer over the toffee.
Chop the reserved 1/4 cup roasted sea salt peanuts and sprinkle them evenly over the melted chocolate.
Let the pan cool to room temperature (about 2 hours) until the toffee and chocolate are set. If you prefer, place the pan in the refrigerator after it has cooled to speed up firming. Cut into pieces and enjoy.