Preheat the oven to 375 degrees. Line a 9 by 12-inch baking sheet with parchment paper.

In the bowl of an electric mixer, preferably fitted with the paddle attachment, beat together the Sunbutter, powdered sugar, 6 tablespoons butter, lemon juice, and 1 teaspoon vanilla until smooth and creamy.

In a food processor, combine 1 ¼ cups chocolate chips, 1 cup butter, the eggs, sugar, cocoa powder, arrow root or starch, salt, and 2 teaspoons vanilla. Process until combined; the mixture will be lumpy. Spread the batter into the prepared pan. Dollop the Sunbutter mixture on the brownie mixture and swirl with a dinner knife.

Bake for 20 – 25 minutes or until the brownies are set and feel slightly firm to the touch, the outer edges will appear drier than the center. Let cool in the pan.

Place the remaining chocolate chips in a heat proof bowl. Heat the cream with the remaining 2 tablespoons butter until it just comes to a boil. Pour the cream over the chocolate chips, let sit for 5 minutes, then stir until smooth and glossy. Spread the chocolate mixture over the top of the cooled brownies then refrigerate for 30 – 60 minutes. Sprinkle the crushed pretzels over the brownies, pressing them gently into the chocolate layer on top.

Remove the brownies from the pan by lifting the parchment paper. Cut into squares and serve.