Winter beginnings are distinguished by the exchange of citrus. On my desk rolls another carrier bag of mandarins; my landlady leaves a tumble of oranges on my doorstep; the latest visit to my sister results in far more limes than I know what to do with. And of course lemons, the abundance of lemons! For weeks my Corso de’ Fiori fruit bowl is a still-life from Vogue Living, and then I notice the limes have turned pallid and the mandarins begin to rot, and I regret the lack of a marmalade-making gene.
Briskly, before they too can wither, I decide for my lemons on a classic lemon tart one weekend when Beef Burgundy to precede it provides an excuse for friends to dinner. That sort of weather. I have scores of lemon tart recipes and the one I settle on, from Elizabeth Luard’s Saffron & Sunshine, is randomly plucked. She calls hers a Tortell de Limon, a Catalan version; it is a triumph, even though in my ‘new’ rather slow oven it takes almost twice as long to bake as specified.
Lemon tarts are one of the stalwarts of restaurant dessert menus, alongside crème brulees, chocolate fondants and panna cottas. There are endless variations on the theme, but credit for the craze must go to the Roux brothers back in the 1980s. One of their signature dishes was Tarte au Citron, or lemon tart, with its tangy creamy custard filling barely trembling within a case of perfect pastry, served at room temperature with a dusting of icing sugar. Indeed its recipe is strikingly similar to Luard’s Catalan version – except that she uses twice the quantity of eggs, a daunting nine. But otherwise there it is, a buttery short pastry par-cooked before being filled with a combination of eggs, sugar, lemon juice and double cream then returned to the oven to bake until the citrus custard has set.
So that’s the classic – but once I started hunting I found other possibilities. One requires that, rather than a custard, you fill the tart shell with a lemon curd: no baking involved at all once you have blind-baked your pastry, and no need to even turn on the oven if the tart shell is composed of a cheesecake-type base of crushed biscuits bound with melted butter. The lemon curd is essentially a sabayon, and needs to be stirred in a bowl over simmering water for 20–25 minutes, until it thickens, and finally enriched with extra butter. (Lemon curd is a useful thing to keep in the refrigerator if you make too much: juice three lemons and grate one finely then whisk into four eggs and one cup caster sugar previously creamed together. With a wooden spoon stir in the top of a double-boiler until very thick then remove from heat and whisk in 125 g chopped unsalted butter.)
Then there are lemon tarts more like cheesecakes, blending cream cheese with sugar, eggs, lemon juice and rind then baked: mere pretenders. One recipe I found called for a filling of sweetened condensed milk, double-whipped cream, lemon juice and lemon rind: another no-cook no-brainer. Thomas Keller’s version uses the sabayon filling but a sensational base incorporating ground pine nuts into the pastry.