Spray 20 cm-square baking pan with non-stick vegetable cooking spray. Line with sheet of wax paper or parchment paper cut to fit pan. Spray paper with cooking spray. Sprinkle about 3 tablespoons flour in pan and shake to coat well. Shake out excess flour. Cream butter in electric mixer bowl on medium speed. Gradually add 1 cup brown sugar, packed. Beat until well blended. Beat in egg, then vanilla. Combine 1 cup flour, nutmeg, cinnamon, salt and baking soda in separate bowl. Beat into creamed mixture. Batter will be thick. Add grated apples and nuts. Mix just until incorporated. Scrape batter into prepared pan. Bake at 350 degrees until cake is firm and wood pick inserted into center comes out clean, 30 to 35 minutes. Remove and cool 10 minutes. Invert cake onto serving platter and remove pan and paper. To prepare icing, combine half cup brown sugar (packed), water, 2 generous teaspoons flour and butter in small heavy saucepan. Cook over medium heat, stirring constantly, until mixture thickens, 3 to 4 minutes. Pierce top of cake with tines of fork and pour icing over cake. Set cake aside to allow icing to firm up. To serve, cut cake into 6 portions and top with scoops of frozen vanilla yogurt. By Betty Rosbottom Copyright Los Angeles Times ----