Blueberry and Lemon Cake
A lemon sponge packed with whole blueberries that stay suspended instead of sinking, finished with a dark blueberry sauce and a snow of zest.
- Total
- 1 hr 10 min
- Prep
- 25 min
- Bake
- 45 min
- Serves
- 10
- Level
- Easy
- Tin
- 20 cm springform
The blueberry problem is gravity. Wet fruit in a loose batter sinks in the first ten minutes of baking, before the crumb sets, and you get a cake with a purple layer at the bottom and nothing above it.
Two small things fix it. The batter is made deliberately thick with yoghurt rather than milk, and the berries go in wearing a coat of flour, which grips the batter instead of sliding through it.
The zest rubbed into the sugar is the other trick worth keeping. It takes one extra minute and doubles the lemon.
Ingredients
For the cake
For the blueberry sauce
You will need
- 20 cm springform tin
- Fine grater
- Small saucepan
Method
Oven 175°C · fan 155°C · 345°F
Heat the oven and line the tin
Heat the oven to 175°C / 155°C fan. Butter a 20 cm springform tin and line the base with baking paper.
Rub the zest into the sugar
Grate the zest of all three lemons straight onto the sugar and rub it in with your fingertips for a minute, until the sugar is damp and smells strongly of lemon. This gets far more flavour out than adding zest to the batter later.
Tip Zest before you juice. A zested lemon still juices; a juiced lemon is impossible to zest.
Cream, then add the eggs
Beat the lemon sugar with the butter for 4 minutes until pale. Add the eggs one at a time, with a spoonful of flour each time.
Fold in the dry ingredients and yoghurt
Fold in the flour, baking powder and salt, then the yoghurt and lemon juice. The batter should be thick enough to hold a ribbon on the spoon for a second.
Toss the berries in flour
Toss the blueberries with the extra tablespoon of flour until dusty, then fold them in with three or four strokes. The flour coat is what keeps them suspended.
Tip Frozen berries work, but fold them in still frozen and add 5 minutes to the bake.
Bake for 45 minutes
Level the top, bake for 45–50 minutes until a skewer comes out clean. If it browns fast at 30 minutes, lay a piece of foil loosely over the top.
Make the sauce
Simmer the sauce blueberries with the sugar and lemon juice until they burst, about 6 minutes. Stir in the slaked cornflour and cook one minute more until it coats the back of a spoon.
Top and serve
Cool 20 minutes in the tin, then release. Scatter fresh blueberries and a little more zest over the top, and pour the warm purple sauce over each slice.
Baker's notes
- The yoghurt is doing two jobs: acid for lift, fat for keeping quality. Sour cream or buttermilk work the same way.
- This is the best cake here for making a day ahead. The lemon comes forward overnight.
Keeping it 4 days in a tin at room temperature, or 5 in the fridge. Freezes well whole, wrapped, for 2 months.
Questions, answered
Why do my blueberries always sink?
Two reasons: a batter too loose to hold them, and un-floured fruit. This batter is deliberately thick, and the tablespoon of flour on the berries gives them grip.
Can I use frozen blueberries?
Yes, and do not thaw them. Thawed berries bleed into the batter and turn the whole crumb grey-purple.
If it goes wrong
Three things account for most of what happens to a cake in a domestic oven. Each has its own guide.
- It sank in the middleSeven causes, told apart by the shape of the crater.
- It came out raw in the centreBrown outside, wet inside, and how to rescue the one you are holding.
- The caramel seizedIt is almost always fixable. The lump re-melts.
