Preheat the oven to 180°C and grease a 25cm springform tin with oil.
Simmer apples with half the lemon juice and two tablespoons of sugar in a covered pan until soft.
Mash the apples roughly with a fork and allow them to cool.
Blend apple purée, eggs, ground almonds, essence, remaining sugar, and remaining lemon juice in a food processor.
Pour the batter into the tin and sprinkle with flaked almonds.
Bake for 40 minutes at 180°C until a skewer comes out clean.
Cool slightly before removing from the tin and dust with icing sugar to serve.