Instructions

• Preheat oven to 350°F. Line a 9 x 13-inch pan with nonstick foil or regular foil sprayed with cooking spray; set aside.
• In a medium bowl, combine 1 1/2 cups graham cracker crumbs, 1/3 cup sugar, and 6 tablespoons melted butter; mix until evenly moistened. Press the mixture firmly and evenly into the bottom of the prepared pan.
• Bake the crust for 10 minutes. Remove from oven and let the crust cool completely in the pan before continuing.
• Divide the 10 ounces bittersweet chocolate chips into two equal portions and set aside.
• Place one portion of the chocolate chips in a microwave-safe bowl. Microwave in 30-second intervals, stirring between each interval, until the chocolate is melted and smooth. Let the melted chocolate cool until just warm (not hot).
• In a large bowl, beat the 8 ounces cream cheese with an electric mixer until light and fluffy. Add the cooled melted chocolate and beat until combined and smooth.
• Reserve 1 cup of the 1 1/2 cups whipping cream for the mousse. In a separate chilled bowl, beat that 1 cup whipping cream with 1/4 cup powdered sugar and 1 teaspoon vanilla until soft peaks form.
• Gently fold the whipped cream into the chocolate–cream cheese mixture until evenly combined. Spread the mousse evenly over the cooled crust. Refrigerate the pan while you make the topping (about 10–15 minutes).
• Place the remaining portion of chocolate chips and the remaining 1/2 cup whipping cream in a microwave-safe bowl. Microwave in 30-second intervals, stirring between each, until the chocolate and cream are melted and the mixture is smooth. Let cool slightly so it is pourable but not hot.
• Spoon the chocolate topping over the chilled mousse and spread to the edges with an offset spatula or the back of a spoon.
• Refrigerate the assembled bars until fully firm, at least 2 hours. Use the foil to lift the bars from the pan, cut into bars, and serve.