Preheat oven to 350°F and line a baking sheet with parchment paper, laying out saltines side by side in a single layer.
Measure 1 heaping cup peanut butter and finely chop 12 ounces of chocolate; set both aside.
In a large saucepan, melt butter, sugar, and salt over medium heat, stirring until amber-colored and reaching 285°F.
Pour toffee over saltines, spreading evenly, and let cool for 5 minutes.
Spread peanut butter over toffee and sprinkle with chopped chocolate.
Bake for 5 minutes, then swirl melted chocolate and top with chopped peanuts.
Refrigerate to set, break into pieces, and enjoy.