Coconut, Pandan and Caramel Mousse Cakes

STEP 1: BAKE THE PANDAN CHIFFON SHEET

Heat the oven to 340°F (170°C). Line the half-sheet pan with parchment; do not grease the sides. Whisk the yolks with 2 tbsp (25 g) of the sugar until pale, then whisk in the oil, coconut milk and 1½ tsp pandan paste. Sift in the cake flour, baking powder and salt, and whisk just to a smooth batter. In a clean bowl, whisk the whites with the cream of tartar to soft peaks, then add the remaining sugar gradually and whisk to glossy, firm but not dry peaks. Fold the meringue into the batter in three additions. Spread evenly into the pan, using the offset spatula to reach the corners, and tap once to release large bubbles. Bake 13 to 16 minutes, until springy and just pulling from the edges. Cool in the pan on a rack, covered with a clean towel so the surface stays soft.

STEP 2: CUT IDENTICAL DISCS AND LINE THE RINGS

Turn the cooled sheet out onto parchment and peel off the bottom paper. Using one of the rings as a cutter, stamp out 24 discs in straight rows (four by six) so every disc comes from the level center of the sheet. Line each ring with an acetate strip and stand the rings on a parchment-lined tray. Press one disc, top side up, into the base of each ring. Chill the tray for 10 minutes so the discs sit firmly against the acetate.

STEP 3: MAKE THE CARAMEL MOUSSE

Sprinkle the 2 tsp gelatin over the 3 tbsp cold water and leave to bloom. In the heavy saucepan, cook the sugar and 2 tbsp water over medium heat, swirling rather than stirring, to a deep amber, about 340°F (171°C). Off the heat, pour in the warm cream in a slow stream (it will bubble violently), then whisk in the butter, salt and bloomed gelatin until dissolved. Cool to about 80°F (27°C): cool enough not to melt whipped cream, warm enough to stay fluid. Whip the cold cream to soft peaks and fold it into the caramel in two additions.

STEP 4: FILL AND STACK BY WEIGHT

Transfer the mousse to a piping bag. Set a ring on the scale and pipe 45 g of mousse over each base disc, working from the center outward so the mousse fills tight to the acetate. Level with the back of a teaspoon. Press a second disc on top, top side up, until it sits level with the others; check by eye across the tray at bench height. Freeze 30 minutes, or chill 1 hour, until the mousse is firm.

STEP 5: MAKE AND POUR THE SET CUSTARD

Bloom the 1 tsp gelatin in the 1 tbsp cold water. Warm the coconut milk with the knotted pandan leaves until steaming, then cover and infuse 15 minutes; remove the leaves, squeezing them out. (If using paste instead of leaves, stir ½ tsp into the warm coconut milk and skip the infusion.) Whisk the sugar, yolks, cornstarch and salt in a bowl, pour in the warm coconut milk while whisking, then return to the pan and cook over medium-low heat, whisking constantly, until it thickens and bubbles for 30 seconds. Off the heat, whisk in the bloomed gelatin and the optional ¼ tsp pandan paste. Strain. Cool, stirring occasionally, to about 100°F (38°C), when it is still pourable; above 110°F (43°C) it will soften the mousse and blur the layer line. Spoon 30 g onto each chilled cake, tilt the ring gently to level, and pop any surface bubbles with a pin. Chill at least 3 hours, or freeze 1 hour for the cleanest unmolding.

STEP 6: MAKE THE ONDE-ONDE

Make these within 2 hours of serving. Steam the grated coconut with a pinch of salt for 5 minutes, then spread out to cool. Cut the pandan leaves into short lengths and blend with the 100 ml water; strain through the fine-mesh sieve, pressing hard, to collect 80 to 90 ml juice. (If using paste, stir ½ tsp into the water instead.) Mix the glutinous rice flour with a pinch of salt, then add the pandan juice gradually, kneading to a soft, smooth, play-dough texture that does not crack; if it cracks, add more juice a teaspoon at a time. Divide the dough into 12 equal pieces of 14 to 15 g, and the gula melaka into 12 portions of 5 g. Flatten each piece of dough into a cup, add a portion of gula melaka, pinch closed and roll smooth; any gap will leak. Drop into a pan of simmering water; once they float, cook 1 minute more so the sugar melts. Lift out with the slotted spoon, drain briefly and roll in the coconut. Keep at room temperature; glutinous rice hardens when chilled.

STEP 7: UNMOLD AND FINISH

Lift each ring off, then peel the acetate away in one smooth pull to reveal straight, layered sides. Transfer the cakes to a serving board with the offset spatula. Set one onde-onde in the dead center of each cake so all twelve match. Rest the cakes 15 minutes at room temperature before serving so the mousse and custard soften to a gooey texture while the onde-onde centers stay molten.