Chocolate Mousse Cake with Raspberry

My niece loves chocolate. I found this recipe from King Arthur Flour web site and made it for her birthday. It was one of the more complicated cakes to make because of the number of ingredients and steps involved. At the end, it was well worth it since my niece said it was the best chocolate cake ever :-)

Ingredients

CAKE
1 3/4 cups all purpose flour
2 teaspoons baking soda
1 teaspoon baking powder
1 teaspoon salt
2 cups granulated sugar
1 cup unsweetened cocoa powder
1/2 cup vegetable oil
1 cup buttermilk ( I replaced with 1 cup of milk + 1 TBSP fresh squeezed lemon juice)
1 cup boiling water
2 teaspoons vanilla extract
3 large eggs

FILLING
1 cup heavy cream
1 cup confectioners' sugar
1 teaspoon Instant ClearJel (Could not find this is local grocery store, replaced with 1 pack of Gelatin)
2 tablespoons butter, soft
1 (8 ounce) package cream cheese, at room temperature
1/2 teaspoon vanilla extract
2/3 cup semisweet chocolate chips, melted
1/2 cup semisweet chocolate mini chips
1 1/2 to 2 pints fresh raspberries

FROSTING
1/2 cup butter-flavored vegetable shortening
1/2 cup (8 tablespoons) unsalted butter
1/4 teaspoon salt
4 cups confectioners' sugar, sifted
1/2 cup unsweetened cocoa powder
1/4 cup milk
1 teaspoon vanilla extract

Steps:

For the cake layers: 
1. Preheat the oven to 325°F.
2. Grease and flour two 8" round by 3" deep cake pans, or four 8" round pans. I used three 9" pans.
3. Sift together or whisk the dry ingredients through a strainer into a large mixing bowl.
4. Combine the oil, buttermilk, boiling water and vanilla in a medium bowl or large measuring cup. Add to the dry ingredients and mix well.
5. Scrape the sides and bottom of the mixing bowl, then beat in the eggs, one at a time. Mix on medium speed for another 2 minutes or until smooth.

6. Divide the batter among the prepared pans.
7. Bake for 50 minutes for 3" deep pans, or 28 to 33 minutes for four 8" pans, or 9" layers, until the cake just begins to pull away from the edge of the pan, and a tester inserted in the center comes out with just a few moist crumbs.
8. Remove from the oven and place on a rack to cool completely.

For the filling: 
1. Beat the heavy cream until soft peaks form.
2. Whisk together 1/4 cup of the confectioners' sugar with the Instant ClearJel (Gelatin) and add to the whipped cream.
3. Beat until the cream has stiff peaks; set aside.
4. In a large mixing bowl, cream together the butter, cream cheese, remaining 3/4 cup of confectioners' sugar and vanilla. Mix on medium speed for 2 minutes, or until well-blended and smooth.
5. Add the melted chocolate to the bowl and mix on medium speed for 1 minute, or until light and fluffy.
6. Scrape the mixing bowl, then fold in the whipped cream and mini chocolate chips. Refrigerate the filling until you're ready to assemble the cake.

For the frosting: 
1. In a large bowl, beat together the shortening, butter, and salt. Sift the confectioners' sugar and cocoa through a strainer to remove any lumps, and add to the bowl alternately with the milk. Add the vanilla. Mix on medium-high speed for 2 minutes, or until fluffy.

To assemble the cake:
1. Turn the cooled layers out of their pans. Split them horizontally if you've baked two deep 8" cakes; trim any domes off the tops if you've baked 4 individual layers.
2. Place the first layer on a serving plate (line the edges with strips of waxed or parchment paper to keep the plate clean), and spread it with 1 cup of the filling. Cut 1/2 pint of raspberries in half and place them over the filling, covering its entire surface.

3. Repeat until all the layers are stacked; place the last layer bottom-side up for a flat surface on top. Once the layers are assembled with filling and raspberries, place the cake in the refrigerator or freezer for at least 30 minutes to firm it up; this will make frosting the cake much easier, since the layers are less likely to slide around, and the crumbs from the cake layers will be set.
4. Frost the top and sides of the cake, decorating with more frosting and fresh raspberries.