Chocolate Orange Cake

water

unsweetened cocoa powder ((1 ½ cups))

all-purpose flour ((4 cups))

baking soda

baking powder

salt

unsalted butter (at room temperature)

granulated sugar ((3.75 cups))

eggs

vanilla extract

unsweetened chocolate (finely chopped)

pasteurized liquid egg whites ((3/4 cup, see Note below))

powdered sugar ((6 cups))

salt

unsalted butter (at room temperature (6 sticks))

vanilla extract

Orange gel food coloring

orange oil (or 2 tsp orange extract)

Zest of 2 oranges

citric acid (optional)

orange juice ((2/3 cup))

granulated sugar ((2/3 cup))

semi-sweet chocolate (finely chopped)

heavy cream

Chocolate sprinkles

Chocolate orange slices or other decorations (optional)