Viennetta

Gather the magic shell ingredients.

Place about 2 inches of water in a small pot. Bring to a boil over high heat. Place the chocolate chunks in a medium-sized bowl, then place it on top of the pot with boiling water. The bottom of the bowl should not touch the water, the bowl should be able to rest on the rim of the pot. Turn the heat down to low and let the chocolate melt completely.

Once the chocolate is melted, remove the bowl from the pot and turn off the heat. Add the coconut oil and salt. Whisk until combined. Set aside.

Gather the ingredients. Set out one 14-ounce container of coffee ice cream to soften slightly, 5 to 8 minutes.

Double line the inside of a 1-pound loaf pan with either plastic wrap, parchment paper, or wax paper. Make sure all the sides are fully covered, and to leave some overhanging the sides. If using plastic wrap, make the lining as smooth as possible. If using parchment or wax paper, tape the overhang to the outside of the container.

Once the coffee ice cream is slightly softened, scoop the entire container of ice cream into the pan to make a one-inch layer. Use the back of a spoon or a small offset spatula to smooth it out evenly. Return the remaining ice cream to the freezer until ready to use. Place the loaf pan in the freezer and let it freeze for at least 2 hours.

Remove the vanilla ice cream from the freezer and let it soften for 5 to 8 minutes until softened.

Take the pan out of the freezer and lightly drizzle some magic shell over top of the coffee ice cream. Use the back of a spoon or small offset spatula to spread it into a paper-thin layer. It should set up almost immediately.

Add the pint of vanilla ice cream over top of the magic shell and smooth it out into an even layer. Place it back into the freezer to set for at least 2 hours.

Remove the remaining coffee ice cream from the freezer and let it soften for 5 to 8 minutes, or until just soft enough to scoop out the ice cream.

Take the pan out of the freezer and lightly drizzle the magic shell over top of the vanilla ice cream. Smooth it out into an even, paper-thin layer.

Add the remaining container of coffee ice cream over the magic shell layer. Smooth it out into an even, flat layer. Place it back in the freezer to completely set up for at least 2 hours.

Gather the mascarpone ingredients once the ice cream in the loaf pan is completely frozen and set.

In the bowl of a stand mixer fitted with the whisk attachment, whip together the mascarpone, confectioners' sugar, and vanilla until smooth and well combined.

Stop the machine and scrape down the sides of the bowl. Continue to whisk on medium-low speed while slowly pour in the heavy cream. Continue to whisk until stiff peaks form.

Prepare a pastry bag with the ribbon tip. Fill the pastry bag with the mascarpone cream and set it aside.

Remove the loaf pan from the freezer. Select a platter slightly larger than the pan.

Unmold the Viennetta by placing the serving platter over top of the loaf pan and, while holding it all together, flip it upside down. Remove the pan and peel off the plastic wrap from the frozen ice cream block.

Pipe ribbons of the mascarpone cream back and forth horizontally to the shorter side of the cake.

Using a fine-mesh sieve, dust the top with cocoa powder. Place the ice cream in the freezer until ready to serve, at least 2 more hours or up to overnight.

Slightly heat a knife under hot water to make clean slices.