Sometimes, on a peaceful, grey winter’s day, I take a citrus fruit from the fridge – a lemon, a clementine, a yuzu if I can find one – pierce its skin and squeeze. Not enough pressure to send a bead of juice running down its peel, but just enough for its scent to float, briefly, brightly, on the air. The clean smell of citrus zest, rumoured to reduce stress in humans (cats hate it), is also a smell that invigorates and, at least in my case, sharpens the appetite more effectively than a mountain hike.
Earlier this week I put a little pile of lemons, limes and clementines on the kitchen table. I lifted out the grater, the flat one with the piranha teeth, and rubbed the fruits gently back and forth, each one sending a spray of its essence several inches into the air. A pile of fruit whose grated zest ended up in a delightfully retro mousse and in tiny meringues that we ate with black coffee.
The juice of lemon, limes and oranges is useful enough to sharpen a salad dressing, change the texture of raw seafood in a ceviche or cut through the fat of a slowly simmered lamb stew, but it is in the zest that the real magic lies. I think of it as the soul of the fruit. The trick is, of course, to grate only the very outermost skin, taking great care not to rub through to the white pith, which has nothing but bitterness to offer.
Citrus zest is an endlessly useful resource. On a white cold winter’s day there are few more worthwhile additions to a bowl of chicken broth. Nothing perks up a brassica more successfully (add to the butter in which you toss broccoli, purple sprouting or kale). Add a mixture of grated orange zest and sugar to warm rhubarb, poached pears in white wine, or, as I did the other day, to meringues no bigger than a mouthful.
Passion fruit and lemon mousse
Lemon and clementine zest has the effect here of intensifying the flavour of the passion fruit. Without their intervention, the fruit can be a little shy as a flavouring. The lightness of a mousse depends not only on the quantity of gelatine, but on the level to which the cream and egg whites are whipped. Beat the egg whites only until they hold a soft shape, but are not so stiff that they stand in peaks. Likewise the cream, it should only be whipped until it sits in gentle folds.
Serves 6
passion fruit 8
gelatine 4 leaves
lemon 1
clementine 1
eggs 4
caster sugar 150g
double cream 250ml
grated clementine zest and rose petals a little of each to finish
Place the gelatine in a bowl of cold water and let it soften. Cut the passion fruit in half. Place a small sieve or tea strainer over a small saucepan. Squeeze the passion fruit halves into the strainer, then push the pulp and juice through the sieve, ending up with a dry mass of seeds. You should have about 125ml of juice.
Finely grate the zest from the lemon and clementine and add to the passion fruit juice. Halve and squeeze the lemon, add the juice to the pan. Warm the juice over a low heat, add the softened gelatine, shaking it lightly first to remove any water, stir for a few seconds until it has dissolved then remove from the heat.
Break the eggs, separating the whites and yolks. Put the yolks into a bowl with the sugar and beat until thick and creamy. Whip the cream until thick, but stop before it is stiff enough to stand in peaks. Beat the egg white until stiff.
Fold the juice and gelatine into the yolks and sugar. Fold in the cream and, lastly, the egg whites, firmly but gently, taking care not to knock the air out. The mixture should be light and frothy.
Divide the mousse between six small dishes. Place on a tray and refrigerate for at least four hours until lightly set. Decorate with rose petals and grated zest.
Citrus meringues with chocolate
I have always found tiny meringues, glistening with sugar, irresistible, a crisp puff of sweetness to eat with coffee or a cup of green tea.
Makes about 24
For the meringue:
egg whites 2
salt a pinch
caster sugar 100g
lemon 1
lime 1
orange 1, small
To decorate:
dark chocolate 200g
caster sugar 2 tbsp
You will also need a baking sheet lined with baking parchment.
Set the oven at 200C/gas mark 6. Tip the sugar on to a tray, smooth it level, then place it in the oven until just warm.
Using an electric food mixer beat the egg whites, with a tiny pinch of salt, until thick and airy. Tip in the warm sugar and continue beating for a good 3 or 4 minutes until stiff and glossy.
Finely grate the zest from the lemon, lime and orange. You will need 6 tsp. Gently fold 3 tsp into the meringue. Scoop the meringue in small amounts – about 1 heaped tsp per scoop – on to the baking sheet, leaving plenty of room between them. You should get about 24 small meringues – and may have to use two sheets. Place in the oven, immediately lowering the heat to 140C/gas mark 1-2, and leave for 40 minutes until lightly crisp.
Remove the meringues from the oven and cool. Break the chocolate into a bowl and place over a saucepan of simmering water. Leave, unstirred, until the chocolate has melted. Mix together the reserved zest and sugar. Leaving the meringues on their baking sheet, trickle the melted chocolate over them, then dust with the zest and sugar mix. Leave to set, then serve with coffee or whipped cream.
Email Nigel at nigel.slater@observer.co.uk or follow him on Twitter @NigelSlater
