Castella

Castella (Kasutera) - Nagasaki Honey Sponge Cake

A fine-crumbed, springy Japanese sponge cake with a glossy dark crust, descended from Portuguese 'pão de Castela'. It relies on a long, gentle bake to develop its signature moist texture and deep caramel top.

Prep

25 min

Cook

60 min

Total

85 min

Serves

8 to 10

Difficulty

Medium

Recipe ingredients

• •4 large eggs, about 220 g total, at room temperature; cold eggs will not foam properly
• •150 g (¾ cup) caster sugar, superfine sugar dissolves faster; do not reduce
• •120 g (¾ cup + 2 tbsp) bread flour, high-gluten flour gives the chewy castella crumb; cake flour will produce a cake-like texture, not the traditional bite
• •30 g (2 tbsp) liquid honey
• •15 ml (1 tbsp) mirin, hon-mirin only, not 'mirin-style condiment', which contains salt and acids
• •15 ml (1 tbsp) neutral oil, rice bran or canola, for greasing and dusting
• •1 tbsp bread flour, extra, for the pan

Steps

1. 1 Line a 20 cm (8 in) square or wooden castella mould (伝統的木型) with parchment on the bottom and long sides, leaving overhangs for lifting the cake out. Brush all lined surfaces with a thin film of neutral oil, then dust lightly with bread flour and tap out the excess. Do not grease the bottom of a wooden mould, only line and oil the sides.
2. 2 Set a rack in the lower third of the oven and preheat to 150°C (300°F) conventional, or 140°C (285°F) fan-forced. The long, gentle bake is what gives castella its moist crumb; do not raise the temperature.
3. 3 Place the whole eggs in a large bowl set over a bain-marie of warm water (about 40°C / 105°F) for 2 to 3 minutes to take the chill off; this helps the foam rise and hold.
4. 4 Working in a stand mixer fitted with the whisk (or by hand with great patience), beat the eggs on medium speed until very foamy and pale, about 2 minutes. Gradually stream in the sugar in 3 additions, beating on medium-high between each, then continue to beat until the mixture is thick, pale lemon, and falls from the whisk in a ribbon that holds a figure-eight on the surface for 3 to 4 seconds (about 6 to 8 minutes total). Scrape the bowl frequently.
5. 5 Warm the honey and mirin together in a small pan over low heat just until fluid and combined; do not boil. Drizzle into the foam while mixing on the slowest speed, just until incorporated.
6. 6 Sift the bread flour over the surface in two additions. Fold in with a large spatula using a J-stroke, cutting through the centre, sweeping along the bottom, and turning the bowl a quarter each time. Stop the moment no dry streaks remain; overmixing deflates the foam and is the most common reason castella sinks or turns out tough.
7. 7 Pour the batter into the prepared mould from a low height to avoid trapping large air pockets. Lift the mould and drop it once onto the counter to release the largest bubbles.
8. 8 Bake at 150°C (300°F) conventional for 55 to 65 minutes. Castella is done when the top is a deep, even chestnut brown (almost mahogany at the edges), a skewer inserted in the centre comes out clean, and the surface springs back gently when pressed. Internal temperature should read 95 to 98°C / 203 to 208°F on an instant-read thermometer; an underbake stays gummy in the centre.
9. 9 Immediately on removing from the oven, lift the cake out by the parchment overhangs and drop it once from about 30 cm (12 in) onto the counter. This traditional 'shock' collapses any residual large bubbles and keeps the fine, even crumb. Place on a rack and cool in the mould for 10 minutes, then peel away the side parchment and cool completely on the rack.
10. 10 Once fully cool (at least 2 hours so the crumb sets), trim the dry edges and cut into neat rectangles about 3 × 6 cm (1¼ × 2½ in). Wrap individual pieces in plastic and rest overnight before eating; the flavour matures and the crumb becomes characteristically moist and springy on day two.