Part 1: Baking the Perfect Chocolate Cupcakes

The foundation of our cupcake cake is a deeply flavorful and moist chocolate cupcake. The use of both oil and buttermilk is the secret to a tender crumb that stays fresh for days.

1. Preheat and Prepare: Preheat your oven to 350°F (175°C). Line two standard 12-cup muffin tins with paper liners. This recipe makes exactly 24 cupcakes.

2. Combine Dry Ingredients: In a large mixing bowl, or the bowl of your stand mixer fitted with a paddle attachment, whisk together the all-purpose flour, granulated sugar, sifted cocoa powder, baking soda, baking powder, and salt. Stirring them together at this stage ensures that the leavening agents are evenly distributed, which is crucial for a consistent rise.

3. Combine Wet Ingredients: In a separate medium bowl, whisk together the room temperature eggs, buttermilk, vegetable oil, and vanilla extract until they are fully combined and smooth.

4. Mix the Batter: Pour the wet ingredients into the bowl with the dry ingredients. Mix on low speed until just combined. Be careful not to overmix at this stage; a few small lumps are perfectly fine. Overmixing develops the gluten in the flour, which can lead to tough, dense cupcakes.

5. Add the Hot Liquid: With the mixer still on low, very carefully and slowly pour in the hot coffee or hot water. The batter will be very thin and liquidy—this is completely normal! This “blooms” the cocoa powder, unlocking its deepest flavor, and adds significant moisture to the final product. Scrape down the sides and bottom of the bowl with a rubber spatula to ensure everything is incorporated, and give it one final, brief mix.

6. Fill the Liners: Using a cookie scoop or a measuring cup (a ¼ cup measure works well), divide the batter evenly among the 24 prepared cupcake liners. Fill each liner about two-thirds full. This will give the cupcakes enough room to rise without spilling over the top.

7. Bake to Perfection: Bake in the preheated oven for 18-22 minutes. To check for doneness, insert a toothpick into the center of a cupcake. If it comes out clean or with a few moist crumbs attached, they are ready. If it comes out with wet batter, they need a few more minutes.

8. Cool Completely: Allow the cupcakes to cool in the muffin tins for about 5-10 minutes before carefully transferring them to a wire rack. It is absolutely essential that the cupcakes cool completely to room temperature before you attempt to frost them. Frosting warm cupcakes will result in a melted, soupy mess. This can take at least 1-2 hours.

Part 2: Making the Heavenly Nutella Cream Cheese Frosting

This frosting is the star of the show. The key to a smooth, non-lumpy cream cheese frosting is ensuring your butter and cream cheese are truly at room temperature.

1. Beat the Base: In the bowl of a stand mixer fitted with the paddle attachment, or in a large bowl using a hand mixer, beat the softened cream cheese and softened butter together on medium-high speed for about 3-4 minutes. Scrape down the sides and bottom of the bowl periodically. The mixture should be completely smooth, creamy, and light in color, with no lumps remaining.

2. Incorporate Sugar: Turn the mixer down to low speed and gradually add the sifted powdered sugar, one cup at a time. Mixing on low will prevent a sugar cloud from exploding all over your kitchen. Once all the sugar is incorporated, add the salt and the vanilla extract.

3. Whip It Good: Increase the mixer speed to medium-high and beat for another 2-3 minutes until the frosting is light, fluffy, and airy. Do not overbeat, as cream cheese frosting can sometimes become too thin if whipped for too long.

4. Prepare for the Swirl: Transfer about half of the vanilla cream cheese frosting to a separate bowl. To the frosting remaining in the mixing bowl, add the 1 cup of Nutella. Mix on low speed until the Nutella is just combined. You don’t want to overmix it, just get it incorporated. Now you have two bowls of frosting: one plain cream cheese and one Nutella cream cheese.

Part 3: Assembling the Nutella Swirl Cupcake Cake

This is the fun, creative part! You get to build your edible masterpiece.

1. Arrange the Cupcakes: On a large serving platter, cake board, or a baking sheet lined with parchment paper, arrange your completely cooled cupcakes. They should be placed right next to each other, touching, to form the shape of a single cake. You can create a simple rectangle, a circle, a heart shape, or even a number for a birthday. A 4×6 rectangle is a great starting point.

2. Create the Two-Tone Swirl: To get the beautiful swirl effect, you’ll need a large piping bag fitted with a large star tip (like a Wilton 1M or 2D). To fill the bag, lay it flat on the counter. Spoon the plain cream cheese frosting along one side of the bag, from the tip to the top. Then, spoon the Nutella frosting along the other, empty side of the bag. Try to keep them as separate as possible.

3. Frost the Cake: Squeeze the piping bag until both colors of frosting begin to emerge from the tip. Starting from the outside edge of a cupcake, pipe a generous rosette-style swirl, moving towards the center. Repeat this process for every single cupcake. The magic is that because the cupcakes are all touching, the individual swirls of frosting will also touch, creating the illusion of a single, beautifully frosted cake.

4. Finishing Touches (Optional): For an extra touch of elegance and flavor, you can sprinkle some chopped toasted hazelnuts, mini chocolate chips, or chocolate shavings over the top of the finished cupcake cake.