Gâteau Patate is one of Réunion's most iconic and beloved sweets — a dense, fragrant cake made from mashed sweet potato enriched with desiccated coconut, butter, eggs and the island's famous Bourbon vanilla. It is sold at every market stall on the island, prepared for school fetes and village celebrations, and carried to picnics wrapped in wax paper alongside sandwiches and passion fruit. The recipe is deeply rooted in the island's agricultural heritage: sweet potatoes have been cultivated in Réunion for centuries, introduced from the Americas via Madagascar and the Cape, and they grow prolifically in the fertile volcanic soil of the highlands. Bourbon vanilla — grown on the island since the early 19th century and still one of the world's finest — is the flavouring that elevates this humble cake from simple to extraordinary. The technique is straightforward but rewards attention to detail. The sweet potato must be thoroughly cooked and mashed until completely smooth — any lumps will create uneven pockets in the baked cake. The batter is thick and dense, closer to a pudding mixture than a typical cake batter, and should be pressed rather than poured into the tin. The correct baking temperature is moderate (180°C), allowing the interior to set fully without the top burning. The finished gâteau patate is dense and moist, with a golden-brown crust and a fudgy, coconut-fragrant interior. It slices cleanly only when fully cooled — a warm gâteau will crumble. On the island, it is eaten at room temperature as a dessert or snack, sometimes accompanied by a scoop of vanilla ice cream or a drizzle of rum.
Serves 8
Peel and cut sweet potato into even chunks of about 4 cm. Place in a pot of cold water, bring to a boil and cook for 15–18 minutes until completely tender when pierced with a knife. Drain thoroughly and return to the hot pot for 1–2 minutes over low heat to steam off excess moisture — this prevents a wet batter.
Excess moisture is the enemy of a set gâteau; do not skip the drying step.
Mash the drained sweet potato using a potato ricer or fine masher until completely smooth with no lumps — press through a sieve if needed for a perfectly silky texture. Allow to cool to room temperature before proceeding.
Preheat oven to 180°C (160°C fan). Grease a 20 cm round cake tin generously with butter and line the base with parchment paper. For easy removal, grease the parchment as well.
In a large bowl, combine the cooled mashed sweet potato, desiccated coconut, sugar, eggs, vanilla, melted butter, rum (if using) and salt. Mix with a wooden spoon or spatula until the batter is fully homogeneous — it will be thick and dense, more like a stiff dough than a pourable batter.
Bring eggs to room temperature first; cold eggs can cause the melted butter to solidify in small lumps.
Spoon the batter into the prepared tin and press it down firmly and evenly with the back of a spoon or a spatula, smoothing the top to a flat, even surface. The batter should fill the tin to about 3 cm depth.
Bake in the preheated oven for 35–40 minutes until the top is deep golden brown and a skewer inserted in the centre comes out clean. The cake will feel firm to the touch but still slightly springy — it firms up further as it cools.
Remove from oven and allow to cool in the tin for 15 minutes, then turn out onto a wire rack. Cool completely to room temperature before slicing — at least 1 hour. A warm gâteau patate will crumble when cut; a cooled one slices cleanly and has a fudgy, dense crumb.
The cake firms up significantly as it cools — do not judge doneness by texture alone when warm; a clean skewer is the reliable test.
A tablespoon of dark rum in the batter is traditional on the island and adds a caramelised warmth that complements the coconut beautifully.
Dry the mashed sweet potato well before adding other ingredients — any excess moisture prevents the cake from setting properly.
Bourbon vanilla (from Réunion or Madagascar) makes a noticeable difference in aroma over synthetic vanilla extract; use the real thing if possible.
Toast the desiccated coconut briefly in a dry pan for 2–3 minutes before mixing in — this deepens the coconut flavour and adds a subtle nuttiness.
Add grated zest of 1 lime and 1 tbsp lime juice to the batter for a bright citrus note that balances the sweetness.
Top with toasted shredded coconut pressed onto the surface before baking for a crunchy, golden crown.
Purple sweet potato version: use ube (purple sweet potato) for a striking violet colour and subtly earthier flavour — adjust sugar down slightly as ube is less sweet.
Individual ramekin version: divide batter among 8 greased ramekins and bake at 180°C for 22–25 minutes for elegant individual portions.
Store covered at room temperature for up to 2 days — the flavour and texture actually improve on day two as the coconut absorbs moisture from the sweet potato. Refrigerate for up to 5 days; bring to room temperature before serving as the cold makes it too firm to enjoy fully.
Sweet potato cultivation in Réunion dates to at least the 17th century, when the tuber arrived from the Americas via Madagascar and the Cape of Good Hope. Gâteau patate likely developed during the 18th century as enslaved cooks combined the island's abundant sweet potatoes with coconut and Bourbon vanilla — the latter having been successfully cultivated on Réunion from around 1819 using artificial pollination techniques developed on the island. The cake is now inseparable from Réunion's identity, found at every market and celebration.
Yes — orange-fleshed sweet potato is the most common and gives the cake a warm amber colour. Purple sweet potato (ube) works beautifully and produces a striking violet cake. White sweet potato makes a paler, slightly drier result. Avoid yam, which has a different starch structure and will not set the same way.
The two most common causes are excess moisture in the sweet potato and underbaking. Always dry the mashed potato in a hot pot before mixing, and bake until a skewer comes out completely clean. The cake should also cool completely before cutting — a warm gâteau will always seem underset even when it is correctly baked.
No — the rum is traditional but completely optional. The cake is delicious without it. If cooking for children or non-drinkers, simply omit it; you might add an extra half teaspoon of vanilla to compensate for the flavour depth the rum provides.
Yes, and it is actually better made a day in advance. The coconut hydrates overnight, the flavours meld, and the texture firms to a perfect dense fudginess. Wrap tightly in cling film at room temperature and slice the next day.
On the island it is eaten as a dessert or afternoon snack at room temperature, sometimes with a small scoop of vanilla ice cream. It also works well drizzled with rum syrup or a little condensed milk. It is not traditionally served warm.
Per serving · 8 servings total
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