This is a recipe my Mom had in her recipe collection.

3 cups flour
2 cups sugar, plus 2 T sugar separate
3 tsp. baking powder
3 tsp. cinnamon, add 2 tsp. to batter and  1 tsp to sprinkle on top of cake batter
2 cups shredded zucchini
3 eggs, beaten
1 tsp. vanilla extract
1 cup vegetable oil
1 tsp. salt
1 cup walnuts, chopped

Mix all ingredients and stir well. Grease and flour a 13 X 9 rectangular baking pan. Pour batter into prepared pan. In a small bowl mix chopped walnuts and 2 T sugar. Sprinkle walnut/sugar mixture over the top of the bake batter and sprinkle with reserved 1 tsp. cinnamon. Bake at 350 degrees for 50-60 minutes. Check with a toothpick, if toothpick comes out clean its done.