Add sweetened condensed milk, cream and peanut butter to a bowl. Whisk until well combined. Set aside.
Combine butter, salt and brown sugar in a saucepan. Heat over medium heat until the butter and sugar are melted. Remove pan from heat.
Add the condensed milk/cream/peanut butter mixture to saucepan. Whisk until well combined. If needed, place saucepan back on low-heat and whisk until smooth.
Pour filling into tart pan over the chocolate crust.
Bake for 10 minutes. Remove from oven and place on wire rack to cool completely.
Chocolate Topping
Place chocolate and butter in a bowl.
Combine cream and corn syrup in a saucepan and bring to a low boil.
Pour the cream / corn syrup over the chocolate / butter. Let stand for 5 minutes, then whisk until smooth.
Pour the chocolate topping over the caramel. Place in refrigerator for 1 hour or until chocolate topping has set. Decorate as desired.