Melt all of the chocolate together with the coconut oil (if using) in 30-second intervals, stirring well after each.
Pour half into a parchment-lined 9×9 pan and spread evenly.
Refrigerate until firm.
Reserve the remaining chocolate for the top layer.
Melt the butter in a saucepan.
Stir in the sugar and heavy whipping cream.
Bring to a gentle boil, stirring continuously so the sugar dissolves and the nougat stays smooth.
Stir in the marshmallow creme, peanut butter, vanilla, salt, and powdered sugar until smooth and fluffy.
Spread over the chilled chocolate layer.
Sprinkle the peanuts evenly over the warm nougat and gently press them in.
Warm the heavy whipping cream in the microwave.
Melt the sugar over medium heat until it becomes a smooth amber caramel.
Stir in the butter until melted.
Slowly pour in the warm heavy whipping cream while stirring.
Stir in the vanilla and salt.
Pour the caramel over the peanut layer and spread evenly.
Refrigerate until firm.
Remelt the reserved chocolate in 30-second intervals.
Pour over the chilled caramel layer.
Spread evenly.
Refrigerate until completely set before lifting out with the parchment paper and slicing.
