Preheat the oven to 180°C / 356°F. Grease a 20 cm (8 inch) springform pan with some butter.
20 g butter
In a large bowl, whisk the egg whites with a pinch of salt on high speed until stiff peaks form. Set aside.
3 eggs, 1 pinch salt
In a separate large mixing bowl, use a hand or stand mixer to beat the butter and sugar together until the mixture is thick and creamy.
115 g butter, 115 g sugar
Add the egg yolks one at a time, mixing continuously. Then stir in 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
Sift the flour and salt into another bowl, then carefully fold them with the ground almonds into the batter.
125 g plain flour, ½ teaspoon salt
Gently fold the beaten egg whites into the cake batter.
Add the blueberries, folding gently to avoid bursting them.
300 g blueberries
Pour the batter into the prepared tin and smooth the top. Place in the oven and bake for 30 minutes.
Caramelised Almond Topping
While the cake is baking, prepare the topping: In a saucepan, melt the butter, honey, and sugar together. Add the slivered almonds and stir well to coat them in the mixture.
100 g slivered almonds, 50 g butter, 50 g sugar, 2 tablespoon honey
After the cake has baked for 30 minutes, remove it from the oven. Carefully spoon the hot almond topping over the surface of the cake (be cautious—it's very hot!).
After a further 15-20 minutes test if the cake is done by pricking a skewer in the middle. If it comes out clean it is done. The almonds on the top should have caramelized while baking.
Once baked, run a thin knife along the edge of the pan to loosen the cake. Allow it to cool completely before removing from the pan and serving.
Video
Notes
*If the cake is still not done, but the almonds are browning too much you can cover the cake with some foil or baking paper while baking.