Six-Layer Dark Chocolate & Strawberry Buttercream Cake
Ingredients
For the Cake:
  • 1-1/2 cups 180 g all-purpose flour
  • 1-1/3 cups 275 g sugar
  • 1/2 cup 60 g dark cocoa powder
  • 1-1/4 teaspoons 6 g baking soda
  • 1-1/4 teaspoons 6 g baking powder
  • 1 teaspoon 5 g salt
  • 140 ml 5 liquid oz buttermilk
  • 130 ml 4.5 liquid oz espresso or strong, hot brewed coffee
  • 75 ml vegetable oil
  • 2 eggs room temperature, lightly beaten
  • 1 tablespoon 15 ml pure vanilla extract
For the Strawberry Swiss Meringue Buttercream:
  • 5 large fresh egg whites (150 g)
  • 1-1/4 cups 250 g sugar
  • 1-1/2 cups 3 sticks(340 g) butter, cut into cubes and cool, but not cold
  • 2 teaspoons 10 ml pure vanilla extract
  • 1/4 cup 59 ml(or to taste) strawberry puree OR a handful (about 1 cup, or more to taste) of fresh, washed, and dried strawberries, chopped
  • pinch of salt
  • few drops pink food colouring optional
For the Glaze:
  • 4 oz 115 g high quality bittersweet chocolate, coarsely chopped or callets
  • 1/3 cup 76 g unsalted butter, at room temperature and cut into cubes
Instructions
For the Cake:
  1. Preheat oven to 350° F (180°C). Prepare three 6-inch round cake pans with butter, parchment paper rounds, and flour or cocoa powder. Tap out excess.
  2. In bowl of electric mixer, sift all dry ingredients.
  3. Add all remaining ingredients to bowl with the dry ingredients and with paddle attachment on mixer, mix for 2 minutes on medium speed (you may need the plastic splash-guard that comes with mixer) and pour into prepared pans. If possible, use digital kitchen scale and weigh pans for even layers. Batter will be liquidy.
  4. Bake for 20 minutes and rotate pans in oven. Cakes are done when toothpick or skewer comes out with a few crumbs, about 30 minutes total. Try not to over-bake.
  5. Cool on wire racks for 20 minutes then gently invert onto racks until completely cool.
For the Strawberry Swiss Meringue Buttercream:
  1. If using strawberry puree, place a handful of frozen strawberries in a food processor, and process until a smooth puree. Measure approximately 1/4 cup and set aside (you may want to add more puree to taste).
  2. Wipe the bowl of an electric mixer with paper towel and lemon juice, to remove any trace of grease. Add egg whites and sugar, and simmer over a pot of water (not boiling), whisking constantly but gently, until temperature reaches 160°F, or if you don't have a candy thermometer, until the sugar has completely dissolved and the egg whites are hot.
  3. With whisk attachment of mixer, begin to whip until the meringue is thick, glossy, and the bottom of the bowl feels neutral to the touch (this can take up to 10 minutes or so). *Don't begin adding butter until the bottom of the bowl feels neutral, and not warm.
  4. Switch over to paddle attachment and, with mixer on low speed, add butter cubes, one at a time, until incorporated, and mix until it has reached a silky smooth texture (if curdles, keep mixing and it will come back to smooth). *If mixture is too runny, refrigerate for about 15 minutes and continue mixing with paddle attachment until it comes together. Add vanilla and salt, continuing to beat on low speed until well combined.
  5. Add strawberry puree to taste or the finely chopped strawberries, and blend until combined. Add small amount of pink food colouring, if desired.
For the Glaze:
  1. Place the chocolate and butter in a medium heatproof bowl over a pot of simmering water. Stir the mixture using a rubber spatula until melted and smooth. *Be careful to not get even a droplet of water into your bowl of chocolate and butter.
Assembly of the Six-Layer Dark Chocolate & Strawberry Buttercream Cake
  1. Slice the 1st cake layer in half horizontally, using a large serrated knife and place cut side up on your cake board, pedestal, or plate.
  2. Using a small offset palette knife, spread approximately 1/2 cup of buttercream evenly on the top.
  3. Repeat this with remaining cake layers, until you come to the final layer, which you will place face-down on the top of the cake.
  4. Place cake on a turntable (if possible), and using a small offset palette knife for the top of the cake, and medium straight palette knife for the sides, cover the cake in a thin layer of buttercream to seal in crumbs. Refrigerate for 30 minutes (or more). *This does not need to be perfect, as that will come with the top "coat" of buttercream.
  5. Repeat the previous step and for best results, use bench scraper held at 90° against the side of the cake, slowly turning the turntable and keeping your hand steady--let the turntable do the work. Clean up edges with your small offset palette knife.
  6. Chill cake.
  7. If glazing the cake, make the glaze and set aside for a few moments to cool a bit. Pour glaze over chilled cake, smoothing the top with a clean small offset palette knife.
  8. Chill again to set.
  9. *Bring to room temperature before serving--about 2+ hours. Never serve Swiss Meringue Buttercream until it is soft and room temperature.