Peppermint Marshmallow Bars

Position a rack in the upper third of an oven and preheat to 350°F (180°C). Line an 8- or 9-inch (20- or 23-cm) square baking pan with parchment paper, leaving enough overhang on the sides to easily remove the bars after they’re baked.

To make the bars, in a large bowl, using a handheld electric mixer, beat together the butter and brown sugar on medium speed until just fluffy, about 3 minutes. Add the egg and vanilla and beat until well combined, about 1 minute.

In a medium bowl, whisk together the flour, graham cracker crumbs, baking powder and salt. Add the flour mixture to the butter mixture and beat on medium speed until combined, about 2 minutes. Stop the mixer and use a rubber spatula to finish incorporating the cookie dough.

Press about two-thirds of the dough into the prepared pan (you can just eyeball it) and press into a thin layer. If the dough feels sticky, dip your fingers in flour and keep pressing. Set aside the pan and the bowl with the remaining cookie dough.

To make the marshmallow crème, in a heatproof bowl, combine the egg whites, granulated sugar, cream of tartar and salt. Set the bowl over a saucepan filled with 2 inches (5 cm) of simmering water. Be careful not to let the bottom of the bowl touch the water.

Using either a handheld whisk or the cleaned electric hand beaters, whisk constantly until the sugar is dissolved and the mixture has thinned and become foamy across the top, about 4 minutes. To test if the egg whites are ready, lightly and quickly dip your finger (the mixture will be hot) and rub the mixture between your fingers to feel for any sugar granules. Heat until the mixture is entirely smooth and a thermometer registers about 160°F (71°C).

Remove from the heat and add the vanilla and peppermint extracts. Using the handheld electric mixer, beat on high speed until stiff, glossy peaks form, about 5 minutes.

Spread the marshmallow crème evenly on top of the crust in the pan; it will be sticky but do your best to create an even, sticky layer. Spraying a rubber spatula with nonstick cooking spray will help. Layer the chocolate chips on top.

Press and mold the remaining cookie dough into large, flat pieces and layer them on top of the chocolate chips and marshmallow crème, leaving seams open to let the chocolate and marshmallow peek through.

Bake until the top is lightly golden brown, 26 to 30 minutes. Transfer the pan to a wire rack and let the bars cool completely, about 1 hour at room temperature or 30 minutes in the refrigerator.

Using the overhanging parchment, lift the bars out of the pan and place on a cutting board. Cut into squares. Cover leftover bars and store at room temperature for up to 1 week. Makes 12 bars.

Courtesy of Joy the Baker