CAKE:Mix flour, sugar, and baking soda in a large bowl. Add in the eggs, pineapple along with its juice, and the pecans, if using. Stir just until moistened. Pour into a buttered 9x13-inch baking pan. Bake in a preheated 350°F oven for about 35 minutes or until toothpick comes out clean. Cool completely. ICING:Combine cream cheese, butter, confectioners sugar, and vanilla. Beat until smooth. Frost cake using all the frosting.