This Thermomix® lemon traybake yields 20 slices and stays moist for 4 days. The secret: 6 eggs, 300 g sugar, 250 ml sunflower oil, 250 ml buttermilk, 500 g flour, 1 sachet baking powder, juice and zest of 4 unwaxed lemons. The oil keeps the cake moister than butter would, and the buttermilk gives the crumb a light, open texture. After 25 minutes at 180 °C, on goes the soaking glaze: 200 g icing sugar plus 60 ml lemon juice, poured over the hot cake so it soaks into every pore.
We bake this cake for nursery birthdays, office bake-ins, and summer garden parties. 20 slices means one tray is enough for a medium-sized gathering and nobody has to bake a second one.
Thermomix® Lemon Cake
Ingredients 0 / 9 ✓
- 6 eggs
- 250 grams sugar
- 1 sheet vanilla sugar
- 400 grams butter
- 50 grams lemon juice
- 400 grams flour
- 1 sheet baking powder
- 300 grams powdered sugar
- 30 grams lemon juice
Instructions 0 / 7
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1
Preheat oven to 180 °C top and bottom heat (160 °C convection oven). Cover a baking tray with baking paper.
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2
Insert butterfly whisk into mixing bowl. Add eggs, sugar, and vanilla sugar to the mixing bowl and mix for 1 min./speed 4.
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3
Remove butterfly whisk, cut butter into pieces, add with lemon juice, flour, and baking powder to mixing bowl and mix for 30 sec./speed 4.
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4
Spread batter evenly on baking sheet and bake on middle rack for 20 to 25 minutes until still light.
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5
After baking, puncture the cake several times with a fork.
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6
Add the powdered sugar and lemon juice to the mixing bowl and mix for 10 sec./speed 4.
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7
Spread the icing generously over the warm cake and allow to cool.
Tip: Ideal also for baking the day before, as the flavors become more vibrant when better absorbed.
Video
Nutrition per serving
Which lemons work and which don’t
We use organic lemons because we need the zest. Conventionally grown lemons are coated in waxes and pesticides, and the cake will taste of them. Sicilian Femminello lemons give the most intense flavour but are rarely found in supermarkets. Spanish Primofiori lemons work well and are available year-round. For better juice yield, warm lemons are more productive: rolling them briefly under hot water breaks down the cell walls, giving us around 20% more juice.
Many recipes use the zest of only one lemon, which gives a subtle flavour. We use the zest of four lemons so the cake genuinely tastes of lemon, not just a sweet sponge.
Oil instead of butter for 4 days of moisture
Sunflower oil stays liquid at room temperature whereas butter sets solid. That is why an oil-based batter stays moist even after 4 days, while a butter-based one goes dry by day 2. Food scientist Harold McGee describes this effect in “On Food and Cooking”: liquid fats interfere less with the starch network and lock moisture into the batter.
We also use buttermilk instead of whole milk. The lactic acid activates the baking powder faster and produces an especially fine, even crumb. No buttermilk to hand? Stir 1 tablespoon of lemon juice into 250 ml of milk and leave it for 5 minutes for a comparable result.
The hot soaking glaze is essential
As soon as the cake comes out of the oven, poke about 30 holes across the surface with a wooden skewer. Immediately pour over the glaze made from 200 g icing sugar and 60 ml fresh lemon juice. The hot cake draws the glaze into every pore, which multiplies the lemon flavour roughly threefold. Only once the cake has been soaked should you spread on the classic icing (150 g icing sugar plus 3 tablespoons of lemon juice), which sets into the typical white finish.
Five lemon variations for a change
With poppy seeds (add 50 g to the batter), with blueberries (scatter 200 g over the batter before baking), lemon and almond (100 g ground almonds, 50 g less flour), lime version (swap all lemons for limes for a sharper flavour), or icing-free (dust with icing sugar instead of the glaze for a lighter option).
What goes well with this lemon cake
With coffee we serve whipped cream, and in summer a scoop of vanilla ice cream alongside. For more citrus inspiration try homemade limoncello or lemon muffins. More traybake ideas are in our traybake collection.
Baking temperature and time for a tray
Goes well with: coffee.
Also worth a look: Thermomix® Paradiescreme cake.
We bake at 180 °C top and bottom heat for 25 minutes on the second shelf from the bottom. Fan works too: use 160 °C and the same 25 minutes, or the surface will dry out. Standard baking tray 40 x 30 cm. The deeper roasting tin (40 x 38 cm) needs 3 minutes less because the batter spreads thinner. Test with a skewer in the centre, not at the edge: if it comes out clean, the cake is done. If wet batter clings to it, give it another 3 minutes. The hot soaking glaze goes on straight from the oven so the hot cake can absorb it fully.
