Step by step recipe:

1. 10 min.
   Roll out 200 g Sweetcrust pastry (pâte sablée) into a long rectangle, not too thin (you should have a nice crust after cooking), a little bigger than your cake tin or mould.
2. 10 min.
   Line mould: not easy, so don't be worry if it breaks up into pieces like in the photo...
   
   The advantage of sweet crust pastry is that you can easily patch it up with offcuts.
3. 3 min.
   Your goal is to get an even regular base with sides about 1 inch or 2-3 cm high.
   
   Then put in the fridge.
   
   Preheat oven to 360°F (180°C).
4. 3 min.
   Meanwhile, mix 100 g icing sugar and 100 g ground almonds with a whisk.
5. 5 min.
   Then add 2 egg whites, 3 drops food colouring (green) if desired, and mix with soft spatula or wooden spatula until obtain a soft mix.
   
   Because egg whites can differ in volume or weight, I advise you to add 1 first and mix, and then add remaining egg white in stages until getting the required soft texture.
6. 30 min.
   Spread mixture in pastry case and bake for about 30 minutes.
7. 
   Allow to cool on a rack, then sprinkle with ice sugar.
   
   Serve in fairly thin slices.