Carrot cake sponge

Carrot cake sponge is moist, dense and pleasantly sweet. The carrot gives water and sugar to the batter, and the oil, rather than butter, keeps the crumb soft. The main problem is an underbaked or wet centre, and the usual cause is too much juice from the carrots.

Ingredients and what each one does

• Carrots bring moisture, sweetness and texture. They are 85–90% water, and it is released while baking.
• Flour is the frame.
• Sugar sweetens and holds moisture.
• Oil keeps the crumb soft, even when cold.
• Eggs bind the batter.
• Walnuts add texture and flavour, and their fat adds tenderness. Optional.

How to make it

1. Grate the carrots finely. Coarse shreds stay as separate strands in the crumb and leave raw-tasting pockets; fine shreds heat through more easily.
2. Squeeze out the juice by hand or in a cloth if the carrots are very juicy: excess water thins the batter and can leave the centre wet. How much juice they release depends on variety and freshness, so look at the batter and judge.
3. Mix the eggs with the sugar and oil until combined. You don’t need to whip them.
4. Stir the flour (with baking powder and spices if you like) into the wet mix for 10–15 seconds. Add the carrots and walnuts and mix a few more strokes, just until spread through. The batter is thick, not pourable.
5. Bake about 35 minutes at 170 °C fan. The skewer should come out nearly clean, with a few moist crumbs but no raw batter. Go by that, not the clock: a moist sponge heats through slowly.
6. Cool in the tin for 10–15 minutes, then on a rack. Chill before slicing.

What can go wrong

• Wet, sticky centre. Too much carrot juice, or underbaked. Squeeze the carrots and trust the skewer rather than the timer.
• Carrots and nuts sink. The batter is too thin; it should be thick.
• Dense and rubbery. Overmixed once the flour was in.
• Dry. Overbaked, or too few carrots.

Substitutions

Walnuts can be swapped for pecans or left out. Replacing some of the sugar with brown sugar gives a more caramel flavour and a darker crumb. Butter instead of oil makes a layer that firms up in the fridge.

Storage

Up to 5 days in the fridge; an oil sponge stays soft. Freezes for a month. After a day with its frosting, the flavour usually deepens.