Preheat oven to 350°.
To prepare cake, place granulated sugar and butter in a large bowl; beat with a mixer at medium speed until well blended (about 5 minutes). Add egg substitute, 1/4 cup at a time, beating well after each addition. Beat in 1 teaspoon vanilla and pumpkin.
Lightly spoon flour into dry measuring cups; level with a knife. Combine the flour and next 6 ingredients (flour through nutmeg), stirring well with a whisk. Fold flour mixture into pumpkin mixture.
Spoon batter into a 10-inch tube pan coated with cooking spray. Bake at 350° for 55 minutes or until a wooden pick inserted in cake comes out clean. Cool in pan 10 minutes on a wire rack. Remove from pan; place on wire rack.
To prepare glaze, place powdered sugar and cream cheese in a bowl; beat with a mixer at medium speed until well blended. Beat in 1/2 teaspoon vanilla. Add orange juice, 1 tablespoon at a time, beating well after each addition. Drizzle warm cake with glaze. Cool completely on wire rack. Garnish with orange sections, if desired.