Lemon Custard for Cake

Cooking method

1. Step 1:

   

   Get your ingredients ready.

2. Step 2:

   

   Pour boiling water over the lemons and let them sit in the hot water for a minute — this takes the bitterness out of the zest and makes the lemons easier to scrub clean. Dry them and grate the zest from 2 lemons on a fine grater. Squeeze the juice from all 3 lemons and strain it through a sieve into a saucepan. You'll get about 300 ml (1 1/4 cups) of juice.

3. Step 3:

   

   Add 2 tablespoons of the cold lemon juice to the cornstarch and stir thoroughly until there are no lumps.

4. Step 4:

   

   Add all the zest and half the sugar to the rest of the juice, stir, and heat until almost boiling — but don't let it boil. It happens fast, so don't walk away; keep stirring so the sugar fully dissolves without scorching.

5. Step 5:

   

   While the juice heats, crack the eggs into a heavy-bottomed saucepan. Beat them lightly, then gradually mix in the remaining sugar and the dissolved cornstarch.

6. Step 6:

   

   Now pour the hot juice into the egg mixture, whisking constantly and adding it slowly in a thin stream so the eggs don't curdle. Set the saucepan over medium heat and cook until the cream thickens, about 4 minutes.

7. Step 7:

   

   Take the thickened cream off the heat, add the butter, and stir until smooth.

8. Step 8:

   

   Press the cream through a sieve into a glass bowl.

9. Step 9:

   

   Press plastic wrap directly onto the surface, let it cool on the counter, then refrigerate for at least 30 minutes — or overnight.

10. Step 10:

    

    In the cold it sets up and thickens further. It's very spreadable but not runny, almost like pudding. The flavor is delicate and sweet-tart, but vivid. Keep it no longer than 5 days. It's handy to make ahead, but you can also make it the day you bake.

11. Step 11:

    

    Once chilled, the cream is very easy to spread over and between cake layers — and more besides.