• Preheat oven to 350 degrees and line a 13x9 inch baking pan with non-stick foil.

For the filling:

• In a small bowl blend together the cream cheese, peanut butter, vanilla and salt until fluffy.
  1 package cream cheese, 8 tablespoon peanut butter, 1 teaspoon vanilla extract, 1/2 teaspoon salt
• Slowly mix in the powdered sugar until it is all incorporated and the mixture is uniformly smooth and creamy.
  1 cup powdered sugar
• Blend in the egg and sour cream until well combined. Set aside.
  1 egg, 2 tablespoon sour cream

For the brownies:

• Whisk together all the dry ingredients in a small bowl until uniform in color and set aside.
  1 cup flour, 1/2 cup cocoa powder, 1 teaspoon salt
• Place the butter and espresso powder in a medium, microwave safe bowl. Heat in the microwave until the butter is melted and hot.
  1 cup butter, 1/2 teaspoon espresso powder
• Immediately, whisk both sugars into the hot butter and continue whisking until mostly dissolved and slightly lightened. This can be done by hand or with an electric mixer.
  1 1/2 cup sugar, 1/2 cup brown sugar
• Whisk in the eggs and vanilla until well combined.
  4 eggs, 2 teaspoon vanilla extract
• Fold in the dry ingredients just until incorporated, do not overmix.
• Stir in chocolate chunks and peanut butter chips. Spread about 3/4 of the batter evenly in the prepared pan.
  1/2 cup chocolate chunks, 1/2 cup peanut butter baking bits
• Spoon the filling into a piping bag or zip top bag, snip the tip (or a bottom corner) off the bag and pipe 4 wide lines of filling lengthwise on top of the brownie batter. Spoon the remaining brownie batter in lines perpendicular to the filling. Use a butter knife to swirl the filling into the batter.
• Place the pan in the oven and bake for 35 - 40 minutes or until just barely done. Remove from oven and cool completely.

For the topping:

• Place the chocolate chips in a heat proof bowl, heat the cream and corn syrup in a small glass measuring cup in the microwave or in a small saucepan on the stove just to boiling and pour over the chocolate chips. Let sit for 2-3 minutes, stir until smooth.
  12 ounce chocolate chips, 3 ounce heavy cream, 1 tablespoon corn syrup
• Whisk in vanilla and peanut butter until completely blended. Spread over the cooled brownies and allow to set.
  1 teaspoon vanilla, 6 tablespoon peanut butter
• Cut the brownies into 24 - 2 x 2 inch squares and serve, store leftovers in an air tight container.