Blueberry Sponge Cake Roll
["6 eggs, separated", "3/4 tsp. cream of tartar", "2 c. sugar, divided", "1/2 tsp. vanilla", "1/4 tsp. salt", "3/4 c. all-purpose flour", "1 Tbsp. grated orange peel", "1/3 c. plus 2 Tbsp. orange juice, divided", "confectioners sugar", "3 Tbsp. cornstarch", "2 c. blueberries"]
["Lightly grease 15 1/2 x 1 1/2 x 1-inch jelly roll pan.", "Line bottom with waxed paper and grease again; set aside."]
["eggs", "cream of tartar", "sugar", "vanilla", "salt", "all-purpose", "orange juice", "confectioners sugar", "cornstarch", "blueberries"]