Mint-Chocolate Ice Cream Sandwiches

Directions

1. For the ice cream:
2. Rest a fine-mesh strainer over a medium bowl and set aside.
3. Put the cream and chopped mint (if using) in a medium saucepan. Heat the cream over medium heat until it is scalded—that is, small bubbles form on the edges of the cream and it almost, but not quite, comes to a boil. Let it sit for 30 minutes.
4. Strain the cream through the fine-mesh strainer. Pour the cream back in the saucepan and bring back up to just under a boil. Whisk in the peppermint extract (if using instead of fresh mint leaves).
5. Put the chocolate in a medium bowl and pour the hot cream on top. Add the salt and whisk until the chocolate is completely melted.
6. With a rubber spatula, scrape the chocolate mixture into an airtight container and refrigerate overnight.

1. For the cake:
2. Place a rack in the center of the oven and preheat to 350° F (175°C). Line a 13- by 18-inch (33- by 46-centimeters) rimmed baking sheet with parchment paper, and spray the parchment liberally with nonstick cooking spray. Be sure to spray well; the cake is sticky and you’ll have a hard time removing the parchment paper from it if you skip this step.
3. Bring a saucepan filled partway with water to a very gentle simmer over medium-high heat. Place the chocolate in a medium metal or glass bowl. Place the bowl over (not touching) the barely simmering water in the saucepan and heat, stirring occasionally with a wooden spoon or rubber spatula, until the chocolate is completely melted and smooth. Alternatively, microwave the chocolate in a microwave-safe bowl in 30-second intervals, stirring after each interval, until melted and smooth. Whisk the egg yolks, coffee, and salt into the melted chocolate; set aside.
4. Using a stand mixer fitted with the whisk attachment (or with an electric hand mixer), beat the egg whites on medium speed. When they reach the soft-peak stage (that is, when the tines of the whisk leave a trail in the whites, 2 to 3 minutes), watch them carefully until they reach firm-peak stage, which will just take another 30 seconds to a minute. They should hold a peak when you stop the mixer and lift up the whisk attachment slowly from the whites. Using a rubber spatula, fold one-third of the whites into the yolk-chocolate mixture to lighten it, and then gently fold in the rest of the whites. Gently fold in the flour until it is all incorporated.
5. Pour the batter onto the prepared baking sheet. Using an offset spatula, carefully spread the batter evenly to cover the entire baking sheet. Concentrate on spreading the batter towards the corners and the edges of the sheet—the center will be easier to fill once the edges are filled with batter. Don’t worry about the top being perfectly smooth; it’s more important that the batter be spread evenly so that the cake is the same thickness throughout. Bake for 10 to 12 minutes, or until the top of the cake is firm and dry when you touch it. It may look a bit glossy and wet while baking, but touch it after about 8 minutes to check doneness and continue to test until it is dry to the touch.
6. Let the cake cool in the pan on a wire rack for 20 to 30 minutes. Place the cooled cake in the freezer for at least 30 minutes or up to overnight (in this case, wrapped well with plastic wrap) to make peeling off the parchment easier.
7. Have a sheet of parchment paper ready that is slightly larger than the baked cake surface and set it on a work surface. Remove the cake from the freezer and run a paring knife around the edge of the cake to release it from the sides of the baking sheet. Invert the cake directly onto the sheet of parchment. Carefully peel off the bottom parchment (which is now on top of the cake). Cut the cake in half widthwise, cutting through the parchment underneath as well so you can lift off one half of the cake. Place half of the cake (with parchment underneath) on a baking sheet, cutting board, or large flat platter.
8. Using a stand mixer fitted with the whisk attachment (or with an electric hand mixer or by hand with a whisk), whisk the “ice cream” base on medium speed for 2 to 3 minutes, or until it holds stiff peaks. Use an offset spatula to spread it evenly in a thick layer on top of the cake half that is on the baking sheet. Carefully invert the other half of the cake onto the ice cream base; center it and press it down so it’s relatively flat and even. Make room in the freezer for the cake and place the whole thing in the freezer for at least 6 hours or up to overnight.
9. When ready to serve, peel off the parchment on both the top and the bottom of the cake. Using a hot knife, trim the edges of the cake to get a clean edge. You will end up with a rectangle about 8 by 12 inches (20 by 30 centimeters). Slice the ice cream sandwich cake into 8 pieces, each about 3 by 4 inches (8 by 10 centimeters).
10. Serve immediately, or store in the freezer, wrapped well in plastic wrap, for up to 3 weeks. These are best served after they’ve been removed from the freezer and set out for 10 to 15 minutes before eating to allow the ice cream to soften.