A super moist chocolate cake soaked with a latte-mixture and filled with coffee & vanilla ice cream, latte-soaked graham crackers, fudge sauce, and toasted marshmallows.
Preheat the oven to 350°F / 175°C. Generously butter a 7" springform pan and coat it with sugar.
Add the cocoa powder and freshly brewed espresso to a medium sized mixing bowl. Stir the mixture together until it's cohesive and there's no lumps.
Add in the vegetable oil, sugar, egg, and sour cream. Whisk vigorously until combined.
Add in the flour, baking powder, and salt. Gently fold the dry ingredients into the wet ingredients just until no streaks of flour remain.
Pour the chocolate cake batter into your prepared 7" cake pan. Bake for 25-30 minutes. To check for doneness: I recommend using a thermometer for the best results: when stuck into the middle of the cake the thermometer should read 205°F / 96°C. The cake is also done when the center no longer jiggles and the top becomes more firm.
Allow the cake to rest in the cake pan for at least 15 minutes before transferring it out to a cooling rack.
Fudge Sauce
While the cake is baking, make the fudge sauce. Add the chocolate chips, sweetened condensed milk, and salt to a microwave safe bowl.
Microwave in 30-second intervals, stirring after each interval, until the mixture is completely melted and smooth. Then, add in the butter and stir the mixture until the butter has completely melted. Set aside in the fridge until you're ready to assemble the cake.
Latte Soak
In a small cup or bowl, combine the milk with freshly brewed espresso. Set aside in the fridge until you're ready to assemble the cake.
Filling
Pour the mini marshmallows out on to a baking tray. Use a kitchen torch to torch the marshmallows. (Alternatively, place them under the broiler while keeping a close eye on them.)
Once the cake has completely cooled to room temperature, slice it in half horizontally to get two even pieces. Brush some of the latte soak onto the inside part of both halves.
Line the inside of the springform pan you baked the cake in with plastic wrap.
Place the bottom half of the cake into the pan. Add in ½ of the coffee ice cream and ½ of the vanilla ice cream, then gently smooth the ice cream out into an even layer.
Spread ½ of the fudge sauce over the ice cream, then place a layer of graham crackers over the fudge sauce (you will need to break them apart to fit.)
Brush the graham crackers with the latte soak, then top them off with ½ of the toasted mini marshmallows.
Add on the remaining ice cream and smooth it out into an even layer, followed by the remaining fudge sauce, and another layer of the graham crackers with the latte soak.
Place the top half of the cake on top of the graham crackers - pushing down slightly to secure it. Cover the cake with plastic wrap and leave it in the freezer for at least 6 hours to firm up.
Coffee Swiss Meringue
When you're ready to serve the ice cream cake, make the meringue. Add the egg whites and sugar to a small saucepan. Set the mixture over medium heat and whisk it constantly until it reaches a temperature of 170°F / 76°C.
Pour the egg mixture into a medium sized mixing bowl and add in the salt, corn starch, and espresso powder. Use a hand mixer or stand mixer fitted with the whisk attachment to beat the mixture until stiff peaks form.
Top the cake with the swiss meringue and use a kitchen torch to torch it up. Garnish with the remaining toasted marshmallows and additional graham crackers. Slice, serve, and enjoy!