Premium castella cake with Okinawan black sugar

Line a cast iron tray with parchment, set the two wooden molds on it and line each with parchment folded and creased into a rectangle, with a sheet down the middle.

Separate the yolks and whites. Whisk the yolks to a uniform thick yellow paste.

Whip the whites in the stand mixer on medium to medium high to a meringue; add the sugar and whisk at very high speed to very stiff peaks that do not fall from the inverted whisk.

Add the yolks to the meringue and whisk slowly in an upward motion so as not to destroy the bubbles.

Sift the black sugar, pressing the dense crystals through the sieve, and fold it in with the whisk.

Whisk in the syrup until smooth, then the bread flour until evenly incorporated.

variation: the first attempt, at half the eggs, sugar, black sugar and syrup and 75 g flour, was baked at 350 degrees, browned about 25 minutes, then steamed at 375 on convection, which blew the steam out and made it sink, then without convection for another 20 to 25 minutes; wrapped in parchment, which stuck without oil.

Sprinkle zarame sugar over the bottom of the mold; pour the batter in through a sieve to remove extra bubbles.

Bake at 325 degrees; every two minutes pull the cake out, mist the top with water and stir the batter with a spoon (awakiri, bubble cutting), four times in all.

Raise to 375 with convection to brown the top quickly, about 15 minutes.

Once brown, add the third wooden rack, cover with the steel tray, turn off the convection and reduce to 350 for 25 to 30 minutes to steam.

Remove the wooden racks, spray the parchment with cooking spray, flip the cake out and back upright.

Cool briefly, wrap in cling film and rest overnight; trim the edges and slice.