Blood Orange Polenta Cake (Gluten-Free)

Every winter I wait for blood oranges the way other people wait for asparagus. They turn up sullen and ordinary on the outside, then you cut one open and there’s that bruised, dramatic crimson and a flavour that’s part orange, part raspberry, part something darker and more grown-up. This cake is the best thing I know to do with them: a dense, sticky, almond-and-polenta sponge that drinks a tart citrus syrup until it’s almost a pudding. And, more or less by accident, it happens to be completely gluten-free.

A cake that was never about flour

The classic Italian polenta cake — the kind you find in Sicilian bakeries and, via Claudia Roden and the River Cafe, in half the cookbooks on my shelf — has no wheat in it at all. Its body comes from ground almonds, its texture from coarse cornmeal, and its richness from a frankly alarming amount of butter. That’s worth saying plainly, because “gluten-free dessert” still conjures images of sad, crumbly approximations of the real thing. This isn’t an approximation. It’s a cake that was always gluten-free and never needed an apology.

The lineage matters, because it explains why the recipe behaves the way it does. Almond-based cakes are old news in Sicily and across the western Mediterranean, where the Arab occupation of the ninth to eleventh centuries left behind almonds, sugar and citrus in quantities that reshaped the local sweet kitchen. Marzipan, granita, cassata, the whole Sicilian pastry canon — much of it traces back to that period. Ground almonds were the practical flour of a place with more almond groves than wheat fields, and they make cakes that keep for days rather than staling overnight. When Rose Gray and Ruth Rogers put an almond-and-polenta cake in the first River Cafe Cook Book in 1995, they were codifying something Italian home cooks had been making for generations, not inventing it.

Polenta itself is the newer arrival. Maize came to Italy from the Americas in the sixteenth century and took hold in the poorer north, in the Veneto and Friuli, where it became peasant food before anyone thought to sweeten it. Its migration into a Sicilian-style almond cake is the sort of cheerful mongrel that Italian regional cooking pretends never happens and does constantly. What the corn brings is texture rather than flavour: a faint, sunlit graininess that keeps an otherwise soft, wet cake from feeling like baby food.

The polenta is doing real work here, so don’t be tempted to leave it out for “extra almonds”. Those tiny grains of corn give the cake its signature grit — a faint, pleasing rasp against the soft almond crumb, like fine sand at the bottom of something otherwise smooth. Use fine or instant polenta, not the coarse stuff meant for slow cooking, or you’ll get a cake that feels gravelly rather than textured. Cornmeal from the baking aisle works; so does the “quick-cook” polenta sold in tubes of loose grains. Avoid anything labelled coarse or bramata unless you actively want the cake to crunch.

The twist: char the syrup, just slightly

Here’s my one small deviation from the orthodox recipe. Instead of a plain orange syrup, I let it cook a fraction longer than feels safe, until the edges of the pan start to caramelise and the whole thing smells faintly of burnt sugar and marmalade. That hint of bitterness is what stops the cake tipping into one-note sweetness. Blood oranges are less sharp than ordinary ones, so they need that grown-up edge to keep them from cloying. Watch it like a hawk — there’s maybe thirty seconds between “deep and toasty” and “ruined” — but it’s worth the nerve.

What’s happening chemically is straightforward once you know to expect it. Sugar dissolved in citrus juice simmers along quietly until the water boils off and the temperature climbs; only then do the sugars start to brown and throw off those toasted, faintly bitter caramel notes. You are not making a full caramel — that would set hard and taste scorched — you are catching the syrup at the very first blush of colour at the pan’s edge, then pulling it off the heat and swirling that colour through the rest. If it starts to smell acrid rather than nutty, it has gone too far; tip it out and start again rather than pour bitterness into a good cake.

The other reason to make the syrup properly is that this is how the cake gets its keeping quality. The sponge soaks it up and turns dense and moist, and a well-syruped polenta cake will sit happily under a cloth for four or five days, getting better and stickier as it goes. If you like this trick of a slightly caramelised citrus soak, it’s the same instinct behind the semolina and coconut namoura, where a hot sugar syrup drenches a warm grain cake the moment it leaves the oven.

A note on blood oranges themselves, since the whole cake hangs on them. They are a natural mutation of the sweet orange, their crimson flesh coloured by anthocyanins — the same pigments that redden blackberries and red cabbage — which develop when the fruit ripens through cold nights. That’s why the best of them come from Sicily, grown in the volcanic soil around Mount Etna, where the sharp temperature swing between warm days and cold nights coaxes out the deepest colour. The main varieties you’ll meet are Tarocco, Moro and Sanguinello, and their British season runs roughly from December to March. Moro is the most dramatically dark and the most raspberry-scented; Tarocco is sweeter and only lightly blushed. Any of them work here, so buy whatever the greengrocer has and isn’t charging a ransom for.

Getting it baked right

Almond-heavy cakes brown fast and set slowly, which is a tricky combination. The low oven temperature is deliberate: you want the centre to cook through before the top scorches. If it’s colouring too quickly, lay a loose sheet of foil over the top for the last fifteen minutes. The cake is done when the centre is just set and springs back lazily — a slight wobble is fine, because it’ll firm up as the syrup soaks in and it cools. A skewer will not come out perfectly clean from a cake this moist; look for a few damp crumbs rather than wet batter.

Cream the butter and sugar properly at the start — a full three to four minutes with an electric whisk, until it’s genuinely pale and has visibly grown in volume. This is your only real leavening. Ground almonds are heavy and there’s no gluten to build structure, so the air you beat in now is most of the lift you’ll get. Under-creamed batter bakes dense and squat, which is fine but a little sad. Add the eggs one at a time and don’t panic if the mixture looks curdled after the last one; the almonds will pull it back together.

Prick the cake all over with a skewer the moment it comes out, and pour the syrup over while both are hot. Hot syrup into a hot cake is the trick to even absorption; if either cools, the syrup pools on top and never penetrates. Then leave it strictly alone in its tin until cold. This is not a cake to rush out of the tin warm and proud — it’ll fall apart and you’ll be sad. A springform tin earns its keep here for exactly this reason: you can release the sides once the cake is completely cool and lift it away without any wrestling.

Serving, storing and small variations

A spoonful of crème fraiche or thick Greek yoghurt alongside is all it needs; the sourness cuts the butter beautifully. If you want to make it look like you tried, candy a few thin blood orange slices in the leftover syrup and fan them over the top — simmer them in the syrup for five minutes until translucent, then let them cool on baking paper before arranging.

For storage, keep the cake in the tin or an airtight box at room temperature for up to five days; the fridge dulls the almond flavour and firms the crumb unnecessarily. It also freezes well: wrap slices individually and defrost at room temperature, and you’d struggle to tell them from fresh. Make-ahead cooks can bake and syrup it a full day before serving, which is genuinely when it tastes best.

Out of season, ordinary oranges work perfectly well — just add a little extra lemon juice to the syrup to bring back the sharpness blood oranges have naturally. You can swap a third of the almonds for ground pistachios for a green, more aromatic version, or fold in a teaspoon of fennel seeds, lightly crushed, which sounds odd and tastes wonderful with the citrus. For a floral, more perfumed cake in the same family, the almond, olive oil and orange blossom cake leans on ground almonds the same way but trades butter for oil, and blood orange sits happily alongside the thyme and citrus in this olive oil panna cotta if you fancy building a whole citrus dinner around one crate of fruit. However you make it, this is the cake I reach for when someone says, slightly apologetically, that they can’t eat gluten — and then watch them have a second slice.