A light sweet-potato mousse set with gelatine or agar is topped with agar “marshmallow” caviar made via the cold-oil method. Serves 6. About 45 minutes active plus chill time.
Why you’ll love it
Think toasted marshmallows and sweet potatoes—without the campfire. This recipe pairs a cloud-soft, spice-kissed mousse with tiny pearls of vanilla marshmallow made using agar and the cold-oil technique. It’s vegetarian-friendly, elegant to serve, and far easier than it looks.
Serves: 6
Prep: 25 minutes
Active cooking: 20 minutes
Chill to set: 60–90 minutes (mousse), 15 minutes (oil)
Ingredients
For the mousse
- Roasted sweet potato purée, 300 g (smooth)
- 35% whipping cream, 250 mL (whipped to soft peaks)
- Brown sugar, 40 g
- Ground cinnamon, ¼ tsp
- Pure vanilla extract, ½ tsp
- Fine salt, pinch
- To set (choose one):
- Gelatine, 1½ tsp (powdered; bloom in 2 tbsp cold water), or
- Agar-agar powder, 2 g (vegetarian set)
For the marshmallow caviar (cold-oil agar)
- Neutral oil (very cold; grape-seed or canola), 300 mL
- Granulated sugar, 120 g
- Water, 120 mL
- Glucose syrup, 30 g
- Pure vanilla extract, ½ tsp
- Agar-agar powder, 2 g
Equipment: hand blender or blender, whisk or mixer, small saucepan, thermometer (optional but helpful), squeeze bottle/pipette/spoon, tall glass or jar for the cold oil, fine-mesh sieve.
Method
1) Make the mousse
- In a small saucepan, warm the sweet potato purée with brown sugar, cinnamon, vanilla, and a pinch of salt until steaming.
- Set:
- Gelatine: Stir the bloomed gelatine into the warm purée until fully dissolved.
- Agar: Whisk agar into the warm purée; simmer 1 minute, whisking.
- Cool the mixture to just warm (no hotter than body temp).
- Fold in the softly whipped cream in two additions until billowy and even.
- Spoon or pipe into six serving glasses. Chill 60–90 minutes until softly set.
2) Make the marshmallow caviar
- Place the neutral oil in the freezer 15 minutes (or on ice 30 minutes) until very cold but pourable.
- In a saucepan, combine sugar, water, glucose, and agar. Bring to a gentle boil; simmer 1 minute, whisking. Remove from heat; stir in vanilla.
- Transfer to a squeeze bottle or use a pipette/spoon.
- Hold the bottle a few centimetres over the cold oil and drip steadily to form pearls. Let rest 1–2 minutes to firm.
- Strain through a fine sieve; rinse pearls briefly under cold water to remove oil. Drain well.
3) Serve
- Scoop or pipe the mousse. Shower generously with marshmallow caviar. Serve immediately, or refrigerate up to 2 hours before serving.
Pro tips for flawless spheres
- Oil temperature: The oil must be very cold for clean pearls. If the syrup stops forming spheres, re-chill the oil.
- Flow control: A squeeze bottle yields consistent droplets; a pipette works for micro-pearls.
- Agar timing: Work while the syrup is hot—agar sets as it cools. If it thickens, gently re-warm.
Make it your way
- Vegetarian: Use agar in both mousse and caviar (as written).
- Vegan: Swap dairy cream for chilled full-fat coconut cream; use agar in the mousse.
- No glucose? Use light corn syrup at equal weight to reduce crystallisation.
- Toasted note: Add a few drops of toasted sugar syrup or finish with a quick torch pass over the pearls in a heat-safe bowl.
Storage
- Mousse: Covered, up to 24 hours.
- Caviar: Covered and chilled (lightly syruped with 1–2 tsp water + 1 tsp sugar to prevent sticking), up to 24 hours. Drain before topping.
FAQ
Can I make the mousse without gelatine?
Yes—use 2 g agar. Simmer it 1 minute in the sweet-potato base, cool to just warm, then fold in the cream.
Is this truly vegetarian?
Yes when set with agar. Use coconut cream to make it fully plant-based.
What oil works best for caviar?
Any neutral, light oil (grape-seed or canola). Chill until very cold for clean pearls.
Why did my pearls look irregular?
The oil was too warm or the syrup too cool. Re-chill the oil and re-warm the syrup.
Printable recipe card
Sweet Potato Mousse with Marshmallow Caviar
Serves 6 | Prep 25 min | Active 20 min | Chill to set 60–90 min
Ingredients:
Mousse: 300 g roasted sweet potato purée; 250 mL 35% cream (soft peaks); 40 g brown sugar; ¼ tsp cinnamon; ½ tsp vanilla; pinch salt; set with 1½ tsp gelatine (bloomed) or 2 g agar.
Caviar: 120 g sugar; 120 mL water; 30 g glucose; ½ tsp vanilla; 2 g agar; 300 mL very cold neutral oil.
Method:
- Warm purée with sugar, cinnamon, vanilla, salt. Dissolve gelatine or simmer agar 1 minute. Cool to just warm. Fold in whipped cream. Chill to set.
- Chill oil very cold. Simmer sugar, water, glucose, agar 1 minute; add vanilla. Drip into cold oil to form pearls. Strain and rinse.
- Serve mousse topped with marshmallow caviar.
