Homemade zebra cakes

Heat the oven to 325, lower than usual because the cake layer is so thin.

Mix the cake flour, baking powder, baking soda and kosher salt as the dry mix.

Separate three large eggs; beat the yolks with about half the sugar until pale and thick.

Stream the oil, buttermilk and vanilla into the yolks, then combine the wet with the dry and mix smooth.

On clean beaters, whip the egg whites with all the remaining sugar added at once and the cream of tartar to firm peaks with beaks standing straight up.

Scrape the yolk batter into the whites and fold together to a light fluffy batter.

Spread onto a sheet tray in a thin layer, about seven millimetres, and tap sharply on the counter.

Bake about six minutes, just barely set and barely golden, springing back lightly when pressed.

Trim the over-browned edges while hot and peel the sticky meringue-like film off the surface.

Level the layer to seven millimetres using plastic straws as guides and a fine sawing motion with a sharp non-serrated blade, aiming for 12 centimetre lengths.

Freeze the trimmed cake so it is firm enough to fill, stack and cut without tearing.

For the Swiss meringue buttercream, combine the sugar, salt, cream of tartar and egg whites in the mixing bowl over a barely simmering double boiler.

Warm, rubbing with a flexible spatula, until no grit remains and the mixture is smooth.

Whip from medium up to high until the meringue is glossy, dense and balls up inside the whisk at firm peaks, and is cool to the touch.

Add the butter a piece at a time, waiting for each to incorporate; keep beating through any soupy or curdled stage.

Scrape the bowl thoroughly, beat in a full tablespoon of vanilla paste, and whip until light and airy.

Pipe the buttercream in even rows with a basket weave tip, one layer one way and a second the other, then sandwich the cake strips with light pressure.

Cut hexagons using a cardboard stencil, slightly smaller than the cake to allow for the knife and the coating, cleaning the serrated knife in hot water between cuts.

Chill the sandwiches so the buttercream firms before glazing.

Melt the white chocolate over the double boiler on the lowest heat, keeping it warm without overheating.

Whisk the corn syrup and a quarter cup of hot tap water into a well in the confectioners sugar with a pinch of salt, working out from the centre until smooth, plus a dash of vanilla extract.

Whisk the melted white chocolate into the sugar mixture over the double boiler, then loosen with one to three tablespoons of warm water until pourable.

Test the consistency on a scrap of cake.

Coat the tops first and dry them coated side up on parchment, not face down, then chill until set.

Enrobe each cake on a fork over a rack so the excess drains downward and all six sides are coated, and dry with air circulation.

Melt a small amount of chocolate in the microwave in 20 second bursts on low power.

Pipe the stripes in straight lines with one pastry tip and one stream, continuously across a row, then go back over each one.

Let the chocolate set before lifting the cakes off the rack.