Dark Chocolate Chiffon Cake with Fluffy Rosewater Frosting

Ingredients

• 1 teaspoon (5 ml) pure vanilla extract
• 1/2 cup (120 ml) vegetable oil (I used Sunflower oil)
• 1-1/2 cups (300g) sugar
• 1 teaspoon (5 g) baking soda
• 1/2 cup (120 ml) water, warm
• 1/4 teaspoon (1.5g) salt
• 4 eggs, separated, and room temperature
• 1/2 cup (1 stick)(114g) unsalted butter, room temperature
• 1 cup (130 g) all-purpose flour
• 2 cups (250 g) icing sugar (powdered, confectioners'), sifted
• 3/4 cup (90g) dark unsweetened cocoa powder
• 1/4 cup (59 ml) whipping cream (heavy cream, 35% fat)
• pinch of salt
• 2 teaspoons (10 g) baking powder
• 1/8 teaspoon rosewater, or more to taste (but use sparingly)
• Few drops pink food gel colour (optional)
• 2 egg whites, room temperature