Directions

Place a layer of parchment paper in the bottom of a cookie sheet and set aside.
Heat 7oz of one batch of chocolate in a double boiler, reserving the remaining 3oz for once the chocolate is melted. Stir the 7oz of chocolate until fully melted. Remove from heat and stir in the remaining 3oz of chopped chocolate. Stir until melted and pour onto the parchment paper, spreading into a thin layer, about 1/8th of an inch thick. Set aside and let it set until firm, around 30-45 minutes.
While you're waiting for the chocolate to set, mix the peanut butter, powdered sugar, softened cultured butter, and 1/2 teaspoon salt until well combined.
Once the chocolate is set, spread the peanut butter mixture onto the chocolate in an even layer. We used a butter knife for this, and it just takes a few minutes and a bit of patience to get it in an even layer.
To melt the remaining batch of chocolate, heat 7oz of the second batch of chocolate in a double boiler until fully melted. Remove from heat and stir in the remaining 3oz of the chopped chocolate until smooth and melted. Then pour over the peanut butter layer, using an offset spatula or the back of a spoon to create an even layer of chocolate. Sprinkle with flaky salt or fleur de sel if desired before the chocolate hardens. Set aside until fully set, if it still feels soft after 30-45 minutes, you can pop it in the freezer.
Cut into rustic chunks or pieces and bag or box up for sharing.