Kue Sifon Jeruk

Bahan-bahan (4 porsi)

• 7 egg yolks
• ¼ cup superfine sugar
• ¼ tsp salt
• 4 tablespoons cooking oil
• 2 tablespoons grated orange rind
• 4 tbsp orange juice
• few drops of orange coloring
• 4 oz self-raising flour
• 7 egg whites
• ½ teaspoon cream of tartar (I substitute with 1 tsp lemon juice)
• ⅔ cup superfine sugar