Preheat the oven to 325°F convection (with the fan) or 350°F conventional (without the fan). Spray and line 3, 8, or 9-inch cake pans with parchment paper.

Into a large bowl, sift together cocoa powder, all-purpose flour, salt, baking powder and baking soda. Set Aside.

Whisk the eggs with the vanilla extract until smooth and homogenous in a separate large bowl. Slowly pour the oil into the eggs while whisking to create an emulsion.

Add the sugar to the bowl and whisk until smooth and incorporated.

Alternately add the dry ingredients and milk in 3 additions. I add about 1/3 of each at the same time, then whisk until no lumps remain. Repeat with the remaining flour mixture and milk.

Divide the cake batter between the cake pans and bake in a preheated oven. Bake until a cake tester or toothpick comes out clean or with just a few clinging crumbs. Three layers will bake faster, so begin checking around 20 minutes. They will bake for 25-28 minutes with convection.

Cool for 10 minutes on a wire rack, then run a paring knife around the edge and flip out onto the rack. You can cool them upside down or use a second wire rack to flip them back over.

Cool completely before frosting.

In a small saucepan, add raspberries, lemon juice, and granulated sugar.

Heat over low heat until the raspberries soften and release their juices, stirring and smashing occasionally. Increase heat to medium or medium-low and simmer until the juices evaporate and you are left with a jam that will hold a line on the back of a spoon. Reduce the heat back to low as the jam thickens to keep it from sticking to the bottom and burning.

Strain through a metal sieve to remove seeds into a frozen bowl. No one wants the crunch of raspberry seeds in their buttercream. It is unwelcome, bordering on offensive.

Press through the sieve, then run the silicone spatula over the bottom to release the thick part of the jam. This jam will actually keep more jam from pressing through.

Pour the mixture into a cold or frozen glass or Pyrex bowl and refrigerate until cold. Adding cold jam to the buttercream will keep the frosting nice and thick.

In a small saucepan, bring whipping cream just to a boil. Pour over the chocolate, shake to distribute, and cover the chocolate. Allow to sit for 2 minutes.

Slowly whisk, starting from the center and working your way out to create an emulsion. Sift in the cocoa powder and whisk to incorporate. You can also put it in before the cream, but it has a tendency to clump and create lumps that will not come out.

Add butter to the still-hot ganache. Switch to a silicone spatula and gently stir in one direction until all the butter has melted and incorporated into the ganache.

Place a piece of plastic wrap directly on the surface and allow it to cool to room temperature. You can speed it up by putting it in the fridge and stirring every 10 minutes.

Beat the butter in the bowl of a stand mixer fitted with the paddle attachment until lightened and soft.

Slowly add the powdered sugar, followed by the vanilla and salt.

Once the buttercream has come together, add the raspberry puree 2 tablespoons at a time, up to 1/3 cup, which is half what you made above. You can add additional lemon juice or heavy cream as desired.

Place about 1 cup in a piping bag fitted with a round tip. You can also just cut the piping bag because this is for creating a dam between the layers.

Place the first cake layer on your favorite serving plate or cake stand. Pipe a ring of the raspberry buttercream around the outer edge of the cake layer.

Scoop about half the remaining raspberry jam into the center and spread out with the back of a spoon. Spread raspberry buttercream on top of the jam to level out the layer. You can use the piping bag to apply the buttercream, but you find that easier to control with the jam.

Smooth out the surface of the raspberry buttercream and add the second layer on top. I recommend chilling it for about 20-30 minutes before adding the next layer, but that is up to you!

Repeat the jam and raspberry buttercream with the second layer, placing the third and final layer on top. Chill the cake for 30 minutes (or an hour if you did not chill between the first and second layer.

Spread the chocolate fudge frosting over the top of the cake and its sides, smoothing out with a bench scraper or a large offset spatula, or a combination of both. However, you achieve a smooth surface!