150 g Dark chocolate
125 g Salted butter; cubed
3 Limes; zest of
3 lg Eggs; separated
200 g Caster sugar
70 g Plain flour
This cake rises spectacularly in the oven and sinks a little as it
cools, resulting in a fractured, sugary crust. The recipe makes just
the right amount of batter for a 22 cm tin.
Preheat the oven to 170 C/335 F/gas mark 3. Grease and line the
cake tin, preferably a loose-bottomed one.
Gently melt the chocolate either in short bursts in the microwave or
in a bowl over a pan of simmering water (don't let the bowl touch the
water).
Stir the butter and zest into the chocolate, heating for a short while
longer if necessary, until the butter is melted. Set aside to cool a
little.
Whisk together the egg yolks with 100 g caster sugar until thick,
creamy and far paler in colour. It s the right consistency when the
mixture falling from the whisk leaves a ribbon on the surface of the
mix. Make sure you whisk the yolks and sugar together promptly if the
sugar just sits on top the yolks it will cook the egg, resulting in
rubbery bits of yolk.
In a clean, dry bowl, with an equally clean, dry whisk, beat the egg
whites until completely foamy. Continue to whisk, adding the
remaining 100 g sugar, 1 tb at a time. Whisk well between each
addition of sugar. The mixture will become thicker and glossier until
slowly lifting the whisk out of the mixture leaves a soft peak a
tapering curl of meringue, slightly droopy at its tip.
Fold the egg yolk mixture into the chocolate. Now fold a third of this
chocolatey mixture into the whites. As soon as this is basically
combined but still marbled, add the next third, and so on. Sift in
half the flour. Gently fold until nearly combined, then sift in the
remaining flour and fold until just homogenous. The most important
thing here is to keep as much air as possible in the batter gently
cut through with the spoon, don't beat it and mix only until just
combined.
Spoon the batter into the prepared cake tin and bake for 30-35
minutes. Let it cool in its tin before releasing.
