Preheat the oven to 170°C or 338°F. Grease a 20 cm (8 inches) cake form with some butter.
20 g butter
Using a hand or stand mixer, whisk the sugar and butter until you achieve a thick, creamy consistency.
115 g butter, 115 g sugar
Add the egg yolks to the butter mixture one by one, while mixing continuously. Now add the milk or orange juice, vanilla extract, almond essence and lemon zest.
3 eggs, 2 tablespoon milk, 1 teaspoon vanilla extract, ½ teaspoon almond essence, grated zest of 1 lemon
In a separate bowl, add the egg whites with a pinch of salt and whisk at a high speed until you see stiff peaks.
3 eggs, 1 pinch salt
Now fold this gently into the yolk mixture. Sift the flour and salt into a separate bowl. Now carefully fold in with the mixture.
½ teaspoon salt, 125 g plain flour
Add the blueberries. Try not to mix too vigorously as you do not want the blueberries to be squashed or burst.
400 g blueberries
Pour or spread the cake into the prepared tin.
Melt the butter and the sugar gently on the stove until the sugar has dissolved. Add the almonds and remove the heat.
1 tablespoon butter, 1 tablespoon sugar, 3 tablespoon slivered almonds
Bake the cake for 10 minutes. Remove from the oven (the surface should have hardened and spread the almond mixture on top. Place back into the oven.
Bake for another 35 to 40 minutes. To check if the cake is done, insert a skewer in the middle. If it comes out clean it’s done.
If you want you can dust the cake with icing sugar before serving.