• Preheat oven to 350°F. Grease a 13 x 18 jelly roll pan with butter or spray with Baker’s Joy.
• In a large bowl, whisk together melted butter, milk, sour cream and sugar.
• Whisk in egg and vanilla extract, then whisk in flour, cocoa powder, baking soda and salt.
• Pour batter into prepared jelly roll pan and bake for 20 minutes, or until a toothpick inserted in the center comes out clean.
• Let cake cool for 10 minutes then start on peanut butter layer.

Peanut Butter Layer:

• Cream peanut butter and regular in a stand mixer then add in vanilla and salt.
• Gradually add powdered sugar, one half cup at a time, beating well on medium speed and scrape sides and bottom of bowl as needed.
• When all sugar has been mixed in, icing will appear dry. Add milk, one teaspoon at a time, and beat at medium speed until light and fluffy.
• Spread one thick and even layer on the top of the cake. Then prepare the chocolate glaze.

Chocolate Frosting:

• Combine butter, milk, corn syrup, and vanilla extract in small saucepan and heat over medium heat until butter is melted. Decrease the heat to low, add the chocolate, and whisk until melted.
• Remove from heat, add the powdered sugar, and whisk until smooth. Let chocolate glaze sit for 5 minutes until it has cooled slightly and started to thicken just a little bit.
• Then slowly pour on top and push towards the edges. Let chocolate frosting harden – about 30 minutes.
• Serve!