Grease an 8-inch square baking tin and line with baking parchment, leaving some parchment overhanging on 2 sides to help lift out the cake when it's done. Preheat the oven to 190°C.
Separate the eggs. Beat the yolks and caster sugar together till you get a pale and creamy mixture that leaves ribbons in the batter.
Using a metal spoon, gently fol in the lemon juice, rind and almond flour until well combined.
In a clean bowl, beat the egg whites till they they are stiff enough and form soft peaks.
Using a spatula, gently fold the egg whites into the cake batter until fully incorporated.
Bake the cake for 30 mins till lightly browned on top or until a toothpick inserted into the cake comes out clean.
Take the tin out, leave for 5 minutes before gently lifting the cake out (using the parchment). Let the cake cool completely on a wire rack before dusting with caster sugar.