Nagasaki Castella

Ingredients

• 6 large eggs, at room temperature
• 200 g caster sugar
• 50 g honey
• 2 tbsp warm water
• 1 tbsp mirin
• 180 g strong white bread flour
• 20 g zarame or demerara sugar, for the tin

Before you cook

• Heat the oven to 170C and line a deep 20 cm square tin with baking paper, letting it stand proud of the rim.
• Scatter the zarame sugar evenly over the base of the lined tin.
• Sift the bread flour twice onto a sheet of paper.
• Stir the honey, warm water and mirin together in a small bowl until loose.
• Set a pan of water on to warm for the mixing bowl to sit over.

Steps

1. Crack the eggs into a large bowl and add the caster sugar.
2. Set the bowl over the pan of warm water and whisk until the mixture reaches blood temperature and the sugar has dissolved.
3. Take the bowl off the water and beat the eggs with an electric whisk on high for 8 minutes.
4. Turn the speed to low and beat for 2 minutes more to break up the biggest bubbles, until the batter falls from the beaters in a ribbon that sits on the surface for 5 seconds.
5. Pour in the honey mixture and whisk on low for 20 seconds.
6. Sift the flour over the batter in three additions, folding each one in with a spatula in a slow scooping motion.
7. Keep folding for a full minute after the last flour goes in, because castella batter needs the gluten worked a little.
8. Pour the batter into the prepared tin from a height to knock out large bubbles.
9. Drag a chopstick through the batter in slow figure-of-eight passes for 20 seconds to even out the crumb.
10. Drop the tin onto the worktop twice from a few centimetres up.
11. Bake at 170C for 10 minutes, until the top has puffed and coloured.
12. Open the oven, drag the chopstick through the surface again in two quick passes, then lower the oven to 160C.
13. Bake for a further 45 minutes, until the top is a deep chestnut brown and a skewer comes out clean.
14. Turn the cake out top down onto cling film, wrap it while still warm and leave it overnight at room temperature so the crumb turns moist and dense.
15. Trim the four sides and the browned base, then cut the cake into thick fingers.