Ghoriba with tapered almonds

Ingredients :

 500 g of almonds (poached and hulled)
 1 pinch of gum arabic powder.
 1 teaspoon of chemical yeast
 1 teaspoon of butter
 4 eggs
 250 g of icing sugar
 1 tablespoon of grated lemon zest

Decoration :
 Egg White
 200 g of garnished almonds.