Step 1

Coat the bottom and sides of an 8-by-8-inch baking dish with nonstick spray.

Step 2

In a large bowl, stir to combine the confectioners' sugar, graham cracker crumbs, peanut butter, 1/8 teaspoon salt, and melted butter. Press the mixture into the prepared baking dish and set aside.

Step 3

Place the chocolate and 1/8 teaspoon salt in a medium bowl. Heat the cream in a small saucepan until bubbles start to form around the edges. Pour the cream over the chocolate, let sit for 1 minute and then whisk until completely melted and smooth.

Step 4

Pour the ganache over the peanut butter mixture and refrigerate until the chocolate is cooled and set, at least 45 minutes and up to overnight.

Step 5

Sprinkle evenly with the flaky sea salt. Cut into squares to serve.