Decadent Dark Chocolate Strawberry Mousse Bars

1.Prepare the Strawberry Swirl: Combine strawberries, 2 tablespoons sugar, and lemon juice in a small saucepan. Cook over medium heat for 8-10 minutes, stirring occasionally, until the berries have broken down into a thick sauce. Strain the mixture through a fine-mesh sieve into a small bowl, pressing down on the solids to extract maximum liquid (you should have about 1/4 cup puree). Discard solids.

2.Make the Strawberry Ganache: Heat 1/2 cup heavy cream in a small saucepan until simmering. Remove from heat and pour over the chopped white chocolate in a heatproof bowl. Let stand for 2 minutes, then whisk until completely smooth. Whisk in the reserved strawberry puree until fully incorporated. Set aside to cool slightly.

3.Prepare the Crust: Line an 8x8 inch baking pan with parchment paper, leaving an overhang on two sides for easy removal. In a medium bowl, combine chocolate wafer crumbs and 1/4 cup sugar. Pour in the melted butter and mix until the crumbs are evenly moistened. Press the mixture firmly and evenly into the bottom of the prepared pan.

4.Chill the Crust: Place the crust in the freezer while preparing the mousse, about 15 minutes.

5.Make the Dark Chocolate Base: Place the chopped dark chocolate in a large heatproof bowl. In a small saucepan, heat the milk, vanilla extract, and salt until just simmering. Pour the hot milk mixture over the chopped chocolate. Let sit undisturbed for 5 minutes, then whisk gently until the chocolate is completely melted and smooth. Let this mixture cool to room temperature (about 20-25 minutes), stirring occasionally.

6.Whip the Cream: In a separate large, chilled bowl, whip 1 1/2 cups cold heavy cream and 2 tablespoons powdered sugar until stiff peaks form.

7.Fold the Mousse: Gently fold about one-third of the whipped cream into the cooled chocolate mixture to lighten it. Then, gently fold in the remaining whipped cream until just combined and no white streaks remain. Be careful not to deflate the air.

8.Assemble the Bars: Pour half of the dark chocolate mousse evenly over the chilled crust. Dollop spoonfuls of the slightly cooled strawberry ganache over the mousse layer. Use a skewer or knife to gently swirl the strawberry mixture into the chocolate layer, creating a marbled effect.

9.Top and Chill: Carefully spread the remaining dark chocolate mousse over the top layer. Cover the pan loosely with plastic wrap and refrigerate for at least 3 hours, or until the mousse is firm enough to slice cleanly.

10.Serve: Use the parchment paper overhang to lift the chilled block from the pan. Slice into bars using a sharp, hot knife (run the knife under hot water and wipe dry between cuts) and serve cold.