Introduction

This Chocolate Sea Salt Mousse Cake is a decadent dessert featuring a rich chocolate cake base topped with airy mousse and a glossy ganache finish. The hint of sea salt perfectly balances the deep chocolate flavors, making it an irresistible treat for any occasion.

The image shows a round, two-layer chocolate cake with a darker bottom layer and a lighter, fluffy top layer. The cake is topped with a smooth, shiny dark chocolate glaze sprinkled with coarse sea salt flakes. The cake is sliced into 12 even pieces, but still intact, and is placed on a crumpled light brown paper over a white marbled surface near a window. The edges of the cake have a soft, spongy texture. photo taken with an iphone --ar 4:5 --v 7

Ingredients

75 grams all purpose flour
85 grams granulated sugar

20 grams cocoa powder (natural)
1/4 teaspoon fine sea salt

1/2 teaspoon baking soda
1/2 teaspoon baking powder

65 grams salted butter (soft)
50 grams sour cream (or full fat Greek yogurt)
35 grams espresso (or strongly brewed coffee)

1 large egg
1 teaspoon vanilla extract
50 grams whole milk

1 3/4 teaspoons powdered gelatin
228 grams 70% chocolate
250 grams heavy cream

4 large eggs
100 grams granulated sugar
1/2 teaspoon fine sea salt

60 grams 70% chocolate
60 grams heavy cream
Flaky salt, for garnish

Instructions

Step 1: Preheat the oven to 350°F and place a rack in the center.
Step 2: In a stand mixer bowl, whisk together flour, sugar, salt, baking powder, baking soda, and cocoa powder.
Step 3: Add the egg, butter, sour cream, vanilla, and espresso. Beat until just smooth, then scrape down the sides and bottom of the bowl.

Step 4: Spray a 7-inch metal cake pan with baking spray and pour in the batter. Smooth the top with a spatula.
Step 5: Bake for 12 minutes, then rotate the pan 180 degrees and bake for 8–10 more minutes until a toothpick comes out clean.
Step 6: Cool the cake in the pan for 15 minutes, then remove and cool completely on a rack.

Step 7: For the mousse, sprinkle gelatin over cold milk in a heat-safe bowl and let it sit for 5 minutes to bloom.
Step 8: Add chopped chocolate to the bowl with gelatin. Heat heavy cream until steaming and pour over chocolate and gelatin. Let sit 2 minutes, then whisk until smooth. Set aside at room temperature, whisking occasionally.
Step 9: Separate eggs into two bowls. Add 50 grams sugar and 1/4 teaspoon salt to each. Whisk yolks and sugar until smooth.

Step 10: Place yolk mixture over simmering water and whisk continuously until sugar dissolves and yolks lighten in color. Remove from heat.
Step 11: Gradually whisk the cooked yolks into the chocolate mixture until smooth.
Step 12: Repeat the cooking process with the egg whites, then whip to stiff peaks using an electric mixer.

Step 13: Gently fold the egg white meringue into the chocolate-yolk mixture in three additions until fully combined.
Step 14: Level the cooled cake top with a serrated knife. Place parchment paper on a flat tray and set the cake on it.
Step 15: Place a cake ring or an acetate ring around the cake and tighten it snugly.

Step 16: Pour the chocolate mousse into the ring over the cake. Cover with plastic wrap and refrigerate for at least 8 hours or overnight.
Step 17: For ganache, place chopped chocolate in a bowl. Heat cream until steaming and pour over chocolate. Let sit 2 minutes, then whisk until smooth. Cool for 10 minutes.
Step 18: Remove the mousse cake from the fridge, peel off the plastic wrap, and pour ganache over the mousse layer. Spread evenly to the edges.

Step 19: Refrigerate the cake for 10 minutes to set the ganache.
Step 20: Before serving, remove the cake collar and acetate. Sprinkle flaky sea salt on top.
Step 21: Cut into 8 slices with a thin sharp knife and serve immediately.

Tips & Variations

Use espresso instead of coffee to enhance the chocolate flavor without bitterness.
Substitute sour cream with full-fat Greek yogurt for a tangier mousse.
For a dairy-free option, use coconut cream and a suitable gelatin alternative.

Gently fold the egg whites to keep the mousse light and airy.
Refrigerate the cake overnight for the best flavor and texture.

Storage

Store the cake covered in the refrigerator for up to 3 days. Keep it chilled to maintain mousse firmness and ganache shine. Bring slices to room temperature for about 10 minutes before serving for the best taste. Avoid freezing as it may affect texture.

How to Serve

A dark chocolate cake with two distinct layers sits on white parchment paper over a white marbled surface. The bottom layer is a dense, moist chocolate base that is rich and dark brown. Above it, there is a thick, fluffy mousse-like chocolate layer with a lighter, airy texture, slightly darker than the topping. The top of the cake is covered with a glossy, smooth chocolate glaze that reflects light, sprinkled with coarse white flakes, possibly sea salt, scattered evenly across the surface. A slice is removed, showing the clear separation between the three layers, and the edges of the cut are clean and sharp. photo taken with an iphone --ar 4:5 --v 7

Serve this delicious recipe with your favorite sides.

FAQs

Can I make this cake ahead of time?

Yes, it’s ideal to prepare the cake the day before serving to allow the mousse to fully set. Keep it refrigerated until ready to serve.

What is an acetate ring and can I make the cake without one?

An acetate ring is a clear plastic strip used to shape and support mousse cakes. If you don’t have one, you can use a cake ring or a springform pan to assemble the mousse layer, but be gentle when removing the mold to preserve the mousse shape.