Preheat oven to 350-degrees. Coat a 9-inch round cake pan with non-fat cooking spray; line bottom with wax paper. Coat wax paper with cooking spray, and set pan aside.
Combine first 6 ingredients (brown sugar through vanilla) in a large bowl; stir well, and set aside.
Combine cornmeal, flour, baking powder, spices and salt in another bowl; stir well, and set aside.
Beat egg whites and cream of tartar at high speed of a mixer until foamy. Gradually add 2 tablespoons brown sugar, beating until stiff peaks form.
Gently fold egg whites and cornmeal mixture alternately into molasses mixture, beginning and ending with egg whites. Pour batter into prepared pan. Bake for 35 minutes or until a wooden pick inserted into center comes out clean.
Let cool 10 minutes in pan on wire rack. Loosen cake from sides of pan, using a narrow metal spatula, and turn out onto a wire rack. Carefully peel off wax paper; let cool completely.
Place cake on serving plate; sift 2 teaspoons powdered sugar over cake.
Place cream cheese in a bowl, and beat at medium speed of a mixer until smooth. Add remaining ingredients, and beat until well blended. Serve with cake.