A two-tier 70% cacao dark chocolate cake with a raspberry coulis filling and a mirror glaze on top

My roommates and I have been watching The Summer I Turned Pretty together for the past few seasons, and when the finale rolled around this year, I knew we needed something special to celebrate.

My favorite dessert combo is dark chocolate and raspberry, so when Jeremiah called for a dramatic two-tier 70% cacao cake with raspberry filling and a mirror glaze, I had to agree with him, though he’s wrong about just about everything else.

I couldn’t find a chocolate cake recipe that highlighted 70% cacao, so I used King Arthur Baking’s tried-and-true chocolate cake (with coffee for depth) and layered it with a rich 70% dark chocolate mousse. For the finish, I made a glittery multicolored mirror glaze because honestly, those satisfying cake glaze videos never stopped being fun.

This cake is a project bake, but if you love baking with friends, it’s worth every step.

Ingredients

Chocolate Cake

I doubled this chocolate cake recipe from King Arthur Baking to make my 6 inch and 8 inch round tiers:

• Chocolate Cake Recipe – King Arthur Baking

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Raspberry Coulis

• 12 oz fresh raspberries
• 3 Tbsp sugar
• 2 Tsp lemon juice
• Lemon zest (to taste)

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70% Cacao Chocolate Mousse

• 1 cup hot water
• ½ cup Dutch-process cocoa powder
• 16 oz 70–80% dark chocolate (I used Ghirardelli 72% chips)
• 4 cups cold heavy cream
• 4 Tbsp confectioners’ sugar
• 1 tsp pure vanilla extract

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Mirror Glaze

• 1 cup cold water
• 2 ½ cups sugar
• 1 ½ cups light corn syrup
• 1 cup sweetened condensed milk
• 30 g unflavored gelatin (4 packs Knox gelatin powder)
• 550 g quality chocolate (I used half dark, half white for a marbled look)
• Food coloring or edible glitter (optional)
• Fresh raspberries for garnish

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Directions

Raspberry Coulis

1. Add raspberries, sugar, lemon juice, and zest to a medium saucepan over medium-low heat.
2. Gently mash berries with a spatula as they cook.
3. Remove from heat once mixture begins to simmer.
4. Blend until smooth, then strain to remove seeds.
5. Let cool. Store in fridge or freezer until ready to use.

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Chocolate Mousse

1. In a small bowl, whisk hot water and cocoa until smooth.
2. Melt chocolate in a double boiler (or microwave in 30-second bursts, stirring each time).
3. Stir cocoa mixture into melted chocolate until thick and smooth. Set aside.
4. In a large bowl with a mixer, whip heavy cream, confectioners’ sugar, and vanilla until medium peaks form (about 3 minutes).
5. Gently fold in chocolate mixture until combined (don’t overmix, you still want the whipped cream to be fluffy).
6. Cover and refrigerate at least 2 hours, up to 2 days. Yields ~9 cups.

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Cake Assembly

1. Once cooled, cut each cake into layers (I ended up with 4 cake layers per tier).
2. For each layer:
   • Spread mousse evenly, leaving a shallow divot in the center.
   • Spoon in raspberry coulis, making sure mousse forms a wall to prevent spillover.
   • Top with another cake layer. Repeat until stacked.
3. Coat assembled tiers with mousse, smoothing with a spatula.
   • Tip: Take your time here! The mousse layer must be as flat and even as possible. Any bumps or dips will show under the glaze since it’s reflective. If needed, freeze for 1-2 hours, then add a thin second coat to smooth imperfections.
4. Freeze each tier at least 2 hours.
5. Insert supports (I used bamboo skewers) into the bottom tier, then stack.
6. Freeze assembled cake overnight before glazing.

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Mirror Glaze

1. Bloom gelatin: sprinkle over cold water, let sit 10 min.
2. In saucepan, heat sugar and corn syrup until bubbling. Remove from heat.
3. Stir in sweetened condensed milk, then bloomed gelatin until dissolved.
4. Melt chocolate and stir into gelatin mixture until smooth (avoid bubbles).
5. Add food coloring/glitter if desired.
6. Cool glaze to 96-100°F, strain, then let sit until 86-95°F.
7. Place frozen cake on wire rack over a lined baking sheet.
8. Pour glaze in a circular motion over cake, letting excess drip off.
9. Transfer cake to serving plate, chill at least 2 hours to set.
10. Garnish with raspberries and enjoy!

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Serving

This cake is dramatic, decadent, and absolutely worth the effort; perfect for a finale watch party, birthday, or any occasion where dessert should be the star.