Preheat the oven to 350°F. Line a 9x13-inch baking dish with aluminum foil, letting the edges hang over for easy removal. Spray with cooking spray and set aside.

In a medium-sized microwave-safe bowl, combine the sliced butter and chopped chocolate. Heat in the microwave for 30 seconds and stir. Continue heating in 15-second intervals until fully melted and smooth. Stir in the 2 teaspoons of vanilla extract and set aside.

In a stand mixer fitted with the paddle attachment, mix together the flour, granulated sugar, brown sugar, cocoa powder, baking soda, and salt.

With the mixer on low speed, add the eggs one by one, mixing until thoroughly combined. Increase the speed to medium and let mix for about 2 minutes. Scrape down the sides of the bowl to ensure even mixing.

On low speed, slowly drizzle in the melted chocolate mixture until just blended. Fold in the chocolate chips gently.

In a mixing bowl, beat together softened cream cheese, powdered sugar, peanut butter, and whipped topping until smooth.

Pour half of the brownie mixture into the prepared baking dish. Spread the peanut butter layer evenly across the brownie batter. Top with the remaining brownie batter. If desired, drizzle the melted chocolate bark over the top. Bake for 30-35 minutes or until a toothpick comes out with moist crumbs.

Allow to cool in the pan for at least 15 minutes before lifting out using the foil edges. Cut into squares and enjoy!