Preheat the oven to 360F (180C). Line 3 pans with parchment paper. The ideal pan size is 10 inches (25cm).

1. Manually chop the walnuts.
2. Grind your cookies or biscuits (I prefer Petite Bureau).
3. Add the ground cookies to the walnuts and mix well.
4. Separate your 12 egg yolks from the whites.
5. Mix egg whites until foamy, and add 1-1/2 cup (300g) of your sugar.
6. Mix well, until stiff peaks form.
7. Add your walnut mixture to the egg whites and mix manually.
8. Spread the batter equally across the 3 pans.
9. Bake at 360F (180C) for 20 min. 2 pans on the middle rack and the third on the bottom. After 10 min switch the places of the pans.
10. Melt 1lb (450g) unsalted butter.
11. Add 2 cups (400g) sugar, cook until sugar dissolves and mixture starts boiling.
12. Add the egg yolks, and cook on medium heat mixing at all times. Once it boils it is done.
13. Leave to cool and place in refrigerator for at least 5 hours to thicken (best overnight). It should come out thick to cut.
14. Mix 1 cup (250ml) heavy whipping cream with 2 tablespoons of powdered sugar.
15. Spread about half the custard over the first layer of baked cake.
16. Spread the pineapple over the custard, covering the whole cake.
17. Spread half of the whipped cream over the lined pineapple.
18. Repeat with the second layer but this time, put sour cherries instead of pineapple. Set aside some sour cherries for the top of the cake for decor. Leave a little bit of the custard for the sides and top as well.
19. Refrigerate the cake for 1-2 hours.
20. Mix another 1 cup (250ml) heavy whipping cream with 2 tablespoons of powdered sugar.
21. Spread over the whole cake and decorate with your sour cherries and piping of your choice!