Walnut Carrot Cake with Coconut Cream Cheese Frosting

Name: Walnut Carrot Cake with Coconut Cream Cheese Frosting
Ingredients: 1 tbsp. butter, for greasing pans; 4 eggs plus 2 egg whites, separated, at room temperature; 1⁄2 tsp. cream of tartar; 1⁄2 cup sugar; 1⁄3 cup light brown sugar; 1 1⁄2 cups cups shredded carrot (4 medium); 1 (20-oz.) can crushed pineapple, drained and squeezed dry; 1⁄2 tsp. vanilla extract; 1 cup chopped walnut pieces; 1 cup cornstarch; 1⁄2 tsp. baking soda; 1⁄2 tsp. salt; 3⁄4 tsp. cinnamon; 1⁄4 tsp. ground ginger; 1⁄4 tsp. freshly grated nutmeg