Preheat the oven to 325°F.

1. Lightly grease and flour four 8″ round pans at least 1 ½” deep. If you have parchment rounds, line the pans with parchment and grease the parchment. If you are using a good-quality baking spray, instead, apply just before filling the pans.

Make the cake

1. In the bowl of a stand mixer fitted with the paddle attachment, combine the flour, baking powder, baking soda, salt, sugar and cocoa, pressing any of them that might look lumpy through a sieve as you add them.
2. In a large bowl or measuring cup, combine the oil, buttermilk or yoghurt, boiling water, and vanilla. Add to the dry ingredients and beat at medium speed until the batter is smooth (30 seconds to 1 minute).
3. Scrape the sides and bottom of the mixing bowl, then beat in the eggs one at a time. Mix on medium speed until smooth (another minute).
4. Divide the batter among the prepared pans. The total weight of the cake batter will be about 55 ounces (1534 g). To ensure your layers are all the same size, divide the batter’s weight by the number of layers you’re baking, and weigh the amount into each pan. For four shallow 8″ layers, use about 13 ¾ ounces (384g) batter in each pan.
5. Bake until the cake just begins to pull away from the edge of the pans, and a tester inserted in the centre comes out with just a few moist crumbs (25 to 30 minutes for four 8″ pans). Place on a rack to cool for 15 minutes before running a knife around the edge of each pan, then turn the cakes onto a rack to cool completely. While the cake layers are cooling, make the filling. 

Make the filling

1. In the bowl of a stand mixer fitted with the whisk attachment, beat the heavy cream with 28 g or ¼ c of the confectioners’ sugar until just stiff (do not overbeat). If you have a second bowl for your mixer, use it for the next step. Otherwise, transfer the whipped cream to a medium bowl and refrigerate until needed. Use the mixer bowl (no need to wash).
2. In the bowl of a stand mixer fitted with the paddle attachment, beat the 85 g or ¾ c of the confectioners’ sugar, butter, cream cheese, vanilla, and salt at medium-low speed until smooth. Add the melted chocolate and mix on medium-high speed until light and fluffy (1 minute).
3. Fold the whipped cream into the cream cheese mixture; scrape the bowl, and stir to combine any sticky residue. Finally, fold in the chocolate mini chips if you’re using them.
4. Level the tops of the four individual layers, or split the cake layers horizontally if you’ve baked two deep 8″ cakes.

Assemble the cake

1. If you are using a turntable, place the first layer on it. Otherwise, line the edges of a serving plate with strips of wax or parchment paper before adding the first layer. Spread the cake with one-third of the filling (216 g or 1 cup). Cut 170 g or 1 c  of raspberries in half lengthwise and place them cut-side down over the filling, covering its entire surface. Repeat until all the layers are stacked; place the last layer bottom-side up for a flat surface on top. You will have a cup of raspberries left over for garnish.
2. Once the layers are assembled with filling and raspberries, place the cake in the refrigerator or freezer to firm up (at least 30 minutes). While the cake is chilling, make the frosting.

Make the frosting and final assembly:

1. In a medium bowl, combine the chopped chocolate, cocoa powder, espresso powder and granulated sugar. Add the boiling water. Stir to melt the chocolate, microwaving on half power for 15-second intervals to melt the last few lumps. Whisk until smooth. Let cool to room temperature.
2. In the bowl of a stand mixer fitted with the paddle attachment, beat the butter until smooth and fluffy. Add the chocolate mixture and beat until combined. If the frosting is too soft to frost a cake, refrigerate until just firm enough to spread (10 minutes).
3. Refrigerate the cake until ready to serve. Garnish with fresh raspberries just before serving.