Orange Chiffon Layer Cake

INGREDIENTS

• 2 1/4 cups cake flour
• 1 1/2 cups granulated sugar
• 1 Tbs. baking powder
• 1 tsp. salt
• 1 tsp. dried blood-orange zest, finely ground in a spice grinder
• 1/2 cup canola oil
• 6 whole eggs, separated, plus 2 egg whites
• 1/2 cup fresh orange juice
• 1/4 cup water
• 1/2 tsp. cream of tartar
• 1 lb. cream cheese
• 16 Tbs. (2 sticks) unsalted butter
• 4 cups confectioners’ sugar
• 2 tsp. orange blossom extract
• 1 jar (12 oz.) orange marmalade
• Thinly sliced kumquats for garnish (optional)