Chocolate-Peanut Butter Sheet Cake | World Wide Chocolate

Ingredients

• 1 stick Unsalted Butter (( melted and cooled, plus more, softened, for pan ))
• 1 1/3 cup All-Purpose Flour (( unbleached ))
• 1/2 cup deZaan Holland Terra Rossa 22/24% Dutched Cocoa Powder
• 2 tsp Baking Powder
• 3/4 tsp Kosher Salt
• 4 Large Eggs (( room temperature ))
• 1 1/2 cup Granulated Sugar
• 2 tsp Prova Gourmet Madagascar Bourbon Vanilla Extract
• 1 cup Sour Cream (( room temperature ))
• 1 stick Unsalted Butter (( softened ))
• 1 cup Creamy Peanut Butter (( not natural, such as Jif ))
• 1/4 cup Sour Cream (( room temperature ))
• 1/3 cup Chopped Roasted Salted Peanuts