Step 1

Preheat oven to 350°F. Grease and line a 9-inch round baking pan with parchment paper. Combine the cocoa powder and boiling water in a large glass measuring cup. Set aside to cool completely.

Step 2

In a large bowl, cream together the butter and sugar until light and fluffy, about 5 to 7 minutes. Next, add the eggs, one at a time, beating well after each addition. Stir in the vanilla.

Step 3

In a separate bowl, whisk together the flour, baking soda, baking powder and salt. Gradually add the dry ingredients to the wet ingredients, alternating with the cooled cocoa mixture from Step Make sure to beat the mixture well after each addition!

Step 4

Pour the cake batter into the prepared pan and bake until a toothpick inserted in the center comes out clean, about 25 to 30 minutes. Cool for 10 minutes in the pan and then remove to a wire rack to cool completely.

Step 5

While the cake cools, prepare the cheesecake layer. In a small bowl, beat together the cream cheese, confectioners' sugar and vanilla until smooth. Pour in the melted dark chocolate chips and beat until fully combined.

Step 6

In another medium bowl (or in a stand mixer fitted with a whisk attachment), beat the heavy whipping cream until soft peaks form. Gently fold it into the cream cheese mixture until evenly incorporated. Editor's Tip: For a fluffy, creamy cheesecake, use a light hand when folding the whipped cream into the cheesecake batter. You want to retain as much air as possible from the whipped cream.

Step 7

In a 9-inch springform pan, place the cooled cake layer in the bottom. Next, pour the cheesecake batter over the top and spread in an even layer. Cover and refrigerate until chilled, about 1 hour.

Step 8

In a large bowl, beat cream until it begins to thicken. Then, gradually add the sugar, beating on a medium speed until stiff peaks form; set aside.

Step 9

In another bowl, beat the cream cheese until fluffy, then add the melted white chocolate. Beat until smooth, then gently fold the mixture into the sweetened whipped cream. Editor's Tip: We always suggest gently melting white chocolate on the stovetop using a double boiler as opposed to the microwave since it's more prone to seizing than other types of chocolate. This is because it contains more cocoa butter than its milk and dark chocolate cousins and has a lower melting point. Go low and slow to avoid a big clumpy mess.

Step 10

Remove the cake from the refrigerator and spread the white chocolate mousse over the chilled chocolate cheesecake layer. Return to the refrigerator and chill until set, about 1 hour.

Step 11

Place the chocolate chips into a large bowl. Next, bring the cream to a low boil in a small saucepan. Pour the warm cream over the chocolate chips, then stir until glossy and smooth. Cool slightly, stirring occasionally to prevent lumps. Transfer 3/4 cup of the chocolate ganache to a container with a lid, then cover and refrigerate to reserve for final decoration before serving.

Step 12

Remove the cake from the refrigerator and remove the outer ring from the springform pan. Transfer the cake to a wire rack positioned over a rimmed sheet pan. Then quickly (yet carefully) pour the remaining ganache over the entire cake, allowing it to coat the sides of the cake completely. Carefully tilt the cake to help direct the ganache to any bare spots you might have missed. Editor's Tip: Getting a perfectly even and smooth homemade ganache layer can take practice. Luckily, the chocolate chips pressed onto the sides in the next step will conceal any imperfections, so don't sweat this step too much. For best coverage, check to ensure the ganache is cool enough not to melt the chilled cake when poured, yet warm enough to flow and spread easily over the surface.

Step 13

For garnish, drizzle melted white chocolate over the top of the cake as abstract stripes or zigzags. Then, gently press miniature chocolate chips onto the sides of the cake once the ganache has partially set. Cover (we suggest using a cake carrier with a lid) and refrigerate until chilled. Editor's Tip: Drizzling the warm white chocolate over the ganache before it has fully set will allow it to sink into the surface partially, so you end up with a smooth, uniform top on the finished cake. If your chocolate has set, don't fret. Your cake will still look beautiful. It will just have a bit more texture and dimension on top.

Step 14

Before serving, beat the reserved ganache from Step 11 until it reaches a piping consistency, about 15 seconds. Transfer it to a piping bag fitted with a star tip. Pipe the ganache into rosettes around the top edges of the cake. Slice and serve immediately or refrigerate until serving.