Chocolate Bombe Cake | An Elegant Dessert Made Approachable
Chef Alan TetreaultIn this tutorial: What You'll Need · Baking the Dome Cake · Slicing and Filling · Making Raspberry Mousse · Whipping Ganache into a Filling · Assembling the Bombe · Making Poured Chocolate Ganache · Icing and Smoothing the Bombe · Pouring the Ganache · Decorating with Chocolate Curls and Gold Leaf
A chocolate bombe cake is one of the most elegant desserts a home baker can produce – a perfectly domed cake filled with layers of raspberry mousse and whipped chocolate ganache, all covered in a glossy poured ganache shell. Chef Alan Tetreault of Global Sugar Art walks through every step, from baking in a hemisphere pan to applying edible gold leaf, proving that this show-stopping centerpiece is well within reach.
What You'll Need
- Fat Daddio's 8-inch hemisphere pan – creates the dome shape; available in many sizes, but 8-inch works best for this project
- Chocolate cake mix – Global Sugar Art's own brand (20 oz) fills the pan with one mix; if using a standard grocery-store mix (14 oz), use two
- Guittard 61% dark chocolate wafers – for the ganache; dark chocolate produces the best results
- Heavy cream – 8 fluid ounces (1 cup) per batch of ganache
- Raspberry cake filling – 1 cup of Island Way or similar fruit filling for the mousse layer
- Unflavored gelatin – 1 tablespoon, bloomed in 2 tablespoons of water, to set the mousse
- Buttercream icing – for the base coat before pouring ganache
- Chocolate curls – for decorating the sides of the bombe
- Edible gold leaf – the sprinkle variety (not the foil type); requires a stainless steel bowl and stainless steel spoon
- Cake slicer/leveler – for cutting even layers
- Quick icer tip – for piping a smooth buttercream coat
- Fondant smoother – for smoothing the buttercream before pouring ganache
- Fat Daddio's cake lifter – for transferring the cake to a cooling rack
- 8-inch cardboard cake circle – for unmolding and supporting the bombe
- Plastic wrap – for lining the hemisphere pan before filling
- Piping tip #22 – for piping a whipped ganache border (optional)
- Paintbrush – for applying gold leaf pieces
- Gumpaste poinsettia (optional) – Chef Alan uses one made with Martellato plunger cutters as a topper
Baking the Dome Cake
- Grease the hemisphere pan thoroughly.
- Nestle the hemisphere pan inside a 6-inch or 7-inch round cake pan to keep it stable in the oven.
- Fill with batter – one full Global Sugar Art cake mix (20 oz), or two standard grocery-store mixes.
- Lower the oven temperature to 335–340 degrees F. Because the dome shape is thick, it takes over an hour to bake through.
- Position the pan in the center of the oven, just as for a standard layer cake.
- Cool completely before slicing and filling.
💡 Tip: The lower baking temperature prevents the outside from over-browning while the thick center finishes cooking.
Slicing and Filling
↪ Prepare the hemisphere pan for assembly
Line the inside of the hemisphere pan with plastic wrap before adding any cake layers. This prevents the fillings from sticking and makes unmolding effortless.
↪ Cut the cake into three layers
- Use a cake slicer set to position 2 to make the first horizontal cut.
- Adjust the slicer to position 7 and make the second cut.
- This produces three layers of cake from the single dome.
Making Raspberry Mousse
- Whip 1 cup of heavy cream until stiff peaks form – but stop before it turns to butter.
- Bloom 1 tablespoon of gelatin by sprinkling it over 2 tablespoons of water and letting it absorb fully, then gently heat until dissolved.
- Fold 1 cup of raspberry filling into the whipped cream.
- Pour in the melted gelatin and gently whisk everything together.
The gelatin gives the mousse enough structure to hold its shape when the bombe is unmolded and sliced.
💡 Tip: Strawberry or any fruit filling can be substituted for raspberry – use whatever flavor complements the cake.
⚠️ Warning. Because the mousse contains whipped cream, the finished bombe must be refrigerated until serving. It can sit out for a short time, but it should not be left out overnight.
Whipping Ganache into a Filling
This step uses ganache that has already been made and chilled overnight in the refrigerator (the full ganache recipe appears in the next section).
- Let the chilled ganache come to room temperature.
- Place it in a stand mixer fitted with the paddle attachment.
- Whip for 2–3 minutes until the ganache becomes light, fluffy, and noticeably lighter in color.
The whipped ganache is thick enough to pipe, spread as a filling, or use to ice a cake. Chef Alan also uses it later to pipe a decorative border with a #22 tip.
💡 Tip: This same whipped ganache can be used to pipe truffle centers or as a cake icing – it is extremely versatile.
Assembling the Bombe
With the plastic-wrap-lined hemisphere pan ready and the fillings prepared, assemble the layers from the bottom of the dome upward:
- Place the dome top (the thin rounded piece) into the bottom of the lined pan.
- Spread a thick layer of whipped chocolate ganache over the first layer, going right to the edges. Do not worry about overflow – it will be covered during icing.
- Set the middle cake layer on top and press gently.
- Spread a thick layer of raspberry mousse over the middle layer, again all the way to the edges.
- Place the final (largest) cake layer on top. Flip this piece so the cut side faces up and the original bottom of the cake faces out – this creates a flat, flush base when the bombe is unmolded.
- Press gently to seat the layer into the mousse.
- Refrigerate for 1–2 hours until firm.
💡 Tip: Flipping the top layer so the original cake bottom faces outward gives the bombe a clean, flat base for sitting on a board. The sloped sides from baking would otherwise create an uneven bottom.
Making Poured Chocolate Ganache
The ganache formula is simple – a 2:1 ratio by weight of chocolate to cream.
↪ Standard recipe
| Ingredient | Amount |
|---|---|
| Dark chocolate (wafers or finely chopped) | 16 oz (1 lb) |
| Heavy cream | 8 fluid oz (1 cup) |
↪ Steps
- Heat the heavy cream on the stove until just scalded – look for a few small bubbles along the edges. Do not let it boil; heavy cream burns easily.
- Pour the hot cream over the chocolate in a bowl.
- Stir briefly just enough to push the chocolate below the surface of the cream.
- Cover the bowl and let it sit undisturbed for 5 minutes. The trapped heat melts the chocolate.
- Stir slowly until the ganache is smooth and fully combined.
- If small lumps remain, microwave for 5–10 seconds at a time, stirring between intervals, until completely smooth.
- Let the ganache cool for about 15 minutes before pouring – it is ready when it coats a spatula nicely.
💡 Tip: If using block chocolate instead of wafers, chop it into small pieces with a French knife first so it melts evenly. Semi-sweet chocolate chips also work.
💡 Tip: Small batches lose heat quickly. Covering the bowl during the 5-minute rest is especially important to retain enough heat to melt all the chocolate.
↪ Adjusting ganache thickness
| Purpose | Chocolate (per 8 oz cream) |
|---|---|
| Thin pourable drizzle | 12–14 oz |
| Standard pour (this recipe) | 16 oz (1 lb) |
| Extra-thick coating or truffle filling | 2.5–3 lb |
Icing and Smoothing the Bombe
↪ Unmolding
- Place an 8-inch cardboard circle on top of the filled hemisphere pan.
- Flip the pan over – the plastic wrap lining allows the bombe to release cleanly.
- Peel away the plastic wrap and smooth any surface irregularities.
↪ Applying the buttercream base coat
- Pipe buttercream over the entire surface using a quick icer tip in a pastry bag. Piping avoids the risk of dragging filling out of the cake with a spatula.
- Let the buttercream rest and air-dry for several minutes. If using a crusting buttercream, it will firm up quickly.
- Smooth the surface by pressing a fondant smoother over a piece of paper held against the cake. This knocks down peaks and spatula marks so the poured ganache will have a clean surface to flow over.
💡 Tip: The base coat does not need to be perfect – it just needs to be smooth enough that spatula strokes will not telegraph through the ganache layer.
💡 Tip: Alternatives to buttercream include rolled fondant, sculpting chocolate (rolled out like dough), or marzipan.
Pouring the Ganache
- Transfer the iced bombe to a cooling rack set over a sheet pan, using a cake lifter to move it.
- Pour the ganache from the top, letting it flow down the sides and all the way around the dome.
- Pop any visible air holes with a toothpick while the ganache is still wet – but work quickly, because the cold cake underneath causes the ganache to set fast.
- Let the ganache set for 5–10 minutes before moving the cake to a serving platter.
💡 Tip: Any ganache that drips onto the sheet pan below can be collected and reused – either reheated for another pour or refrigerated and whipped into a filling.
Decorating with Chocolate Curls and Gold Leaf
↪ Applying chocolate curls
- Slide a spatula under the cake and lift it with one hand.
- Scoop chocolate curls with the other hand and press them into the bottom sides of the bombe.
- Work over a sheet pan so the excess curls fall back and can be reused.
This is the same technique used to apply ground nuts, sprinkles, or any other side decoration to a cake.
↪ Piping a ganache border
Use leftover whipped ganache in a bag fitted with a #22 tip to pipe a shell or star border around the base of the bombe where it meets the serving platter.
↪ Applying edible gold leaf
There are two types of edible gold used in culinary applications – gold foil (for covering entire surfaces) and gold sprinkles (for accents). This project uses the sprinkle type.
- Place a sheet of gold leaf in a stainless steel bowl. Do not use plastic or glass – the gold will stick.
- Break the gold into small pieces using a stainless steel spoon or fork. It takes a bit of patience for the sheet to start crumbling.
- Pick up small flakes with a dry paintbrush and dab them onto the surface of the bombe.
⚠️ Warning. The two types of edible gold (foil and sprinkles) are not interchangeable. Make sure to purchase the correct variety for the intended application.
↪ Adding a topper
Chef Alan finishes the bombe with a pre-made gumpaste poinsettia and a few leaves, making it an ideal holiday centerpiece. Any sugar flower, chocolate decoration, or seasonal topper works here.
Cutting and Serving
- Use a sharp, non-serrated knife – a slightly warm or damp blade cuts cleanest through the ganache shell.
- The cross-section reveals the layered interior: chocolate cake, whipped ganache filling, raspberry mousse, and more cake, all encased in the poured ganache glaze.
💡 Tip: This bombe can be customized in many ways – white chocolate ganache, yellow cake, different colored fillings, or alternative fruit mousses. Search "dessert bombe" for inspiration.
This tutorial is part of Global Sugar Art's library of free cake decorating videos by Chef Alan Tetreault. Browse all tutorials →
