Hot Cocoa Bombs: How to Make Them Without the Shells Cracking
Hot cocoa bombs are mostly a chocolate-tempering problem wearing a holiday costume. When they go wrong, the shells crack, bloom grey, or refuse to melt open in the mug.
All three have the same root cause: temperature.
How do you make it?
Makes: 6 cocoa bombs · Prep: 30m · Total: 1h30m
Ingredients
- 8 oz (225 g) good semi-sweet or dark chocolate, chopped
- 6 tbsp (30 g) unsweetened cocoa powder
- 6 tbsp (72 g) sugar
- Pinch of salt
- ½ cup mini marshmallows
- Silicone half-sphere mould, 2.5 in / 6 cm
- Hot milk, to serve
Method
- Melt most of the chocolate. Melt two thirds of the chopped chocolate over a bain-marie to about 115°F (46°C), then take it off and stir in the remaining third until fully melted and it drops to around 88°F (31°C). This quick seeding method is what makes the shells snap instead of bloom.
- Coat the mould. Brush a thick, even layer of chocolate into each half-sphere, taking it right up over the rim. Chill 10 minutes, then apply a second coat. Two thin coats beat one thick one every time.
- Chill and unmould. Chill 20 minutes until the shells pull away from the silicone on their own. Handle them by the edges — fingertips melt them and leave prints.
- Fill. Into each half put 1 tbsp cocoa, 1 tbsp sugar, a pinch of salt and a small handful of mini marshmallows.
- Seal. Press the rim of an empty half onto a warm plate for two seconds to melt it flat, then join it to a filled half. Smooth the seam with a fingertip.
- Serve. Put a bomb in a mug and pour 8 oz of hot milk over it. Wait 30 seconds, then stir.
Why do cocoa bomb shells crack?
Because the shell is too thin, or it was unmoulded too early. Two coats with a chill between them gives a shell strong enough to handle. If it fights the mould, it is not ready — give it another five minutes in the fridge.
Why do they turn grey or streaky?
That is bloom, and it means the chocolate was not tempered. The seeding method in step one handles it without a thermometer-heavy process: melt two thirds, then stir in the last third to bring the temperature down with already-stable crystals in it.
Why did my bomb not open in the mug?
The milk was not hot enough, or the shell was too thick. The milk needs to be near-simmering, not warm from the microwave. If your shells are heavy, pour the milk directly over the top of the bomb rather than around it.
How much cocoa goes inside one?
One tablespoon of unsweetened cocoa and one of sugar per bomb, for an 8 oz mug. Using unsweetened cocoa rather than a pre-mixed drinking chocolate is what lets you set the sweetness — pre-mixed powder in a bomb is usually why the finished drink is cloying.
How far ahead can you make them?
Two weeks in an airtight container at cool room temperature. Do not refrigerate finished bombs: condensation dulls the shell and can make the sugar inside clump.
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Common questions
Why do my hot cocoa bombs crack?
The shell is too thin or was unmoulded too early. Use two coats of chocolate with a chill in between, and only unmould when the shell releases from the silicone by itself.
Why did my cocoa bomb turn grey?
That is chocolate bloom from untempered chocolate. Melt two thirds of the chocolate, then stir in the remaining third to seed it back into temper.
Why did my cocoa bomb not open?
The milk was not hot enough or the shell was too thick. Use near-simmering milk and pour it directly over the top of the bomb.
How long do hot cocoa bombs keep?
About two weeks in an airtight container at cool room temperature. Do not refrigerate them, as condensation dulls the shell.
Where to go next
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.