This mousse is a wonderful celebration of two of the mainstays in our garden at home at Arniano, rosemary and olives. It is a particular joy to make in November using the rich and unctuous new season’s olive oil. Olive oil replaces the usual cream of a traditional mousse, making it simultaneously lighter and yet richer, a happy oxymoron giving a texture like a sweet chocolatey mayonnaise. It’s a combination that was first suggested to me by my dear friend and maestro on our painting courses, William Roper-Curzon. He lives in Greece, where he first tried this dessert, and we often have lively discussions as to the merits of Italian versus Greek olive oil.

Serving the mousse with a drizzle more olive oil and a sprinkling of sea salt is an inspired touch suggested by another friend, Duncan, a quintessential buongustaio (gourmet) who excels at making things just that little bit more delicious, and it does indeed bring this pudding to dizzying new heights.

Serves 4

INGREDIENTS
Mousse
4 rosemary sprigs
120ml very good olive oil
150g very good dark chocolate
Sea salt
4 organic eggs
5 tablespoons caster sugar

To serve
Olive oil
Sea salt

METHOD
Put the rosemary sprigs in a small saucepan and cover with the olive oil. Gently warm over a low heat for about 5 minutes, until a few little bubbles appear. You don’t want the oil to boil or cook too furiously. The moment you see a bubble, immediately turn off the heat and leave the rosemary to infuse for about 20 minutes. (If you’re short on time, don’t worry, just continue with the recipe – your mousse will just be a little less ‘rosemary-y’.)

Pour a little water into a small saucepan and bring to the boil over a high heat. Break the chocolate into pieces and place in a large heatproof bowl with a pinch of salt. Place the bowl over the saucepan, making sure the bottom of the bowl doesn’t have any contact with the boiling water. Leave the chocolate to melt over the boiling water, stirring occasionally. Once almost completely melted, remove the bowl from the heat and stir the chocolate until melted and smooth. Set aside to cool a little.

Separate the eggs, putting the whites into a very clean, dry mixing bowl, and the egg yolks and 4 tablespoons of the sugar into a large serving bowl from which you can serve the mousse later.
Discard the rosemary sprigs and add the olive oil to the melted chocolate bit by bit, stirring well to make sure it’s well amalgamated and smooth.

Using hand-held electric beaters, whisk the egg yolks and sugar for about 2 minutes, until thick and pale. Give the beaters a rinse and whisk the egg whites with a pinch of salt until frothy. Add the remaining tablespoon of sugar and whisk until stiff peaks form. Set aside.

While the melted chocolate mixture is warmish, rather than still very hot, gradually mix it through the beaten egg yolks using a spatula or large spoon. The mixture will be quite thick and dense. Once amalgamated, add a tablespoon of the beaten egg whites, gently folding the rest in bit by bit. I find the best way to do this is to scoop around the rim of the bowl and then cut down through the centre to fold the chocolatey mass with the whites. Repeat until all the egg white is incorporated into the chocolate.

Once amalgamated, scoop off any mousse clinging around the top of the bowl and drop it into the main batch. Give the rim a wipe with a clean tea towel. Leave to set in the fridge for at least 1 hour, or loosely covered overnight.

Remove from the fridge 15 minutes before serving alongside some very good olive oil for drizzling and sea salt for everyone to sprinkle over their mousse.Winter in Tuscany by Amber Guinness, published by Thames & Hudson Australia, AUD$64.99, published 2 September 2025. Images © Valentina Solfrini.