Heat oven 350F. Grease and flour 2 8 or 9 inch round cake pans. In small bowl mix nuts,brown sugar and cinnamon. set aside.
Lightly spoon flour into measuring cup; level off, in large bow, combine flour, sugar, baking powder, salt, milk, margarine and egg. Mix at low speed until moistened. Beat 2 more minutes at meium speed. Spread 3/4 cup batter into each cake pan. Sprinkle 1/4 of nut and sugar mix evenly over batter in each pan. Carefully spread remaining batter on top of nut and sugar mixture in pan. Then, spread remaining nut and sugar mixture on top of batter in pan.
Bake 350 for 20-30 minutes or until toothpick inserted comes out clean. Cool slightly. In small bowl, combine powdered sugar and enough water for desired drizzling consistency; blend until smooth. Drizzle over warm cakes. 2 cakes 6-8 servings each. TIP: Cake can be baked in 13x9 inch pan. 350 for 25-30 minutes or until done.