Grandpa’s Orange Sponge Cake

Ingredients

• 10 large eggs, at room temperature, then yolks and whites separated
• 1 cup white sugar + an additional 1/3 cup reserved for later
• 3/4 cup freshly squeezed orange juice, no pulp
• 1 tablespoon orange zest + more for decoration later
• 1/2 cup vegetable or canola oil
• 2 cups cake flour
• 2 teaspoons baking powder
• pinch salt
• powdered sugar, for dusting