BREAKUP CAKE

Steps:

• For the cake layers: Preheat the oven to 350 degrees F. Coat three 6-by-3-inch heart-shaped cake pans with flour-based baking spray; set aside.
• In a large mixing bowl, whisk together the flour, granulated sugar, cocoa powder, baking powder, baking soda and salt.
• In the bowl of an electric mixer fitted with the whip attachment, combine the eggs, buttermilk, vanilla extract and vegetable oil. Beat on medium-low speed until combined. Reduce the speed to low and add the flour mixture a little at a time. Scrape down the bowl and mix again briefly.
• In a small bowl, combine the boiling water, bittersweet chocolate and espresso powder. Mix until the chocolate is melted and the espresso is dissolved. With the mixer running on low speed, add the chocolate mixture to the batter. Mix until combined. Scrape down the sides of the bowl and mix again until a thin batter forms.
• Divide the batter among the prepared pans, filling each no more than two-thirds full. Bake until the cakes are well puffed and the centers are set, about 30 minutes; a toothpick tester should come out clean or with a few moist crumbs clinging to it when the cake is properly baked. Allow the cakes to cool in the pans for 10 minutes, then turn out to wire racks to cool completely. When the cakes are cool, level the tops using a serrated knife or cake leveler.
• For the pink vanilla buttercream: In the bowl of an electric mixer fitted with the whip attachment, combine the butter and confectioners' sugar. Mix until crumbly, about 1 minute. Add the vanilla extract and beat again on medium-high speed. Lower the speed and add the milk or cream 1 tablespoon at a time to thin the mixture. Beat on high speed until the frosting is thick, white and fluffy. Add the pastel pink gel food color a little at a time until a soft but consistent pastel hue is achieved. Transfer the frosting to a piping bag with a hole snipped in the end.
• Place a cake layer on a serving plate or cake board. Top the cake so that it has a 1/4-inch layer of buttercream; smooth with an offset spatula. Repeat with a second cake layer and more buttercream. Top with the remaining cake layer. Pipe the buttercream all around the edges and top of the cake. Smooth the surface using an offset spatula. Refrigerate the cake until set, about 30 minutes.
• For the marshmallow fondant: Place the marshmallows and 1 1/2 teaspoons water in a large microwave-safe bowl. Microwave in 30-second intervals, stirring well between each, until the mixture can be stirred smooth. This will take about 1 minute to 1 minute 30 seconds.
• Add the confectioners' sugar and stir to combine. When the mixture is too stiff to stir, knead with gloved hands until smooth and pliable. Add more confectioners' sugar if the mixture is sticky or too lax to hold its shape when you roll it into a ball.
• On a confectioners' sugar-dusted work surface, cut the fondant into 6 portions. Tint each portion with one color of each food coloring so that you have a ball of red, orange, yellow, green, blue and purple.
• Roll each color of fondant except the red to 1/8 inch thickness. Using a 2.5-inch heart-shaped cookie cutter, cut out 2 hearts from each piece (you may not use all of the hearts on the cake, but have extra for practice when penning messages). Transfer them to a parchment paper-lined baking sheet and let them dry for 20 minutes, or until the surfaces are dry and firm to the touch.
• Using a red food color marker, pen unromantic messages on each heart, such as NO THX, NOPE, NEXT, BYE, PASS and CYA. Let stand until dry, about 5 minutes.
• Apply dots of leftover buttercream to the backs of the hearts to apply them to the outside of the cake. Press gently because the dry surfaces of the hearts will crack with too much pressure.
• Roll out the red fondant to 1/8 inch thickness. Use 1.5-inch letter fondant cutters to cut out 'ITS OVER'. Use a small paring knife or kitchen-dedicated X-Acto knife to freehand cut a small apostrophe from the fondant. Apply the message to the top center of the cake. Use leftover frosting on the backsides of each letter if they don't stick naturally.
• Refrigerate the cake to set the decors, about 10 minutes. Bring the cake to room temperature before serving for best flavor and texture.