Eucalyptus key lime cake

Melt the white chocolate and butter together slowly over a bain-marie, lowering the heat so it is not steaming.

Brush the bundt pan everywhere with melted butter and dust with sugar so the cake releases.

Whip five egg yolks with a little sugar and lime zest until pale and airy.

In a clean, fat-free bowl whip the egg whites slowly to a foam, then rain in the sugar and whip to soft peak.

Stir the melted chocolate and butter, add the lime juice, and combine with the yolks.

Fold in the flour and the whites in alternating thirds, starting and ending with flour; the first fold can be rougher, the last gentle, reaching the bottom.

Heat the oven to 350F; fill the prepared bundt pan.

Set the pan in a water bath of hot water halfway up with eucalyptus in the water, so its aroma infuses the cake; top up with hot water if it drops.

For the meringue, heat egg whites and sugar over simmering water to 110F, until the sugar dissolves.

Wipe the mixer bowl with a cut lime, whip to glossy hard peaks, and add the juice of half a lime.

Bake 45 minutes; cool, take out of the water, and refrigerate about an hour so the fats set.

Invert the cake out of the pan, warming the mould with a torch if it sticks.

Pipe the meringue over the cake in uneven layers, pull it into peaks, and zest lime over the top, avoiding the bitter white pith.