In a medium bowl, stir together the eggs, oil, zucchini, sugar and vanilla until well blended.
In a separate bowl, combine the flour, baking soda, baking powder, salt and cinnamon.
Add the dry ingredients to the zucchini mixture and stir just until combined.
Divide batter evenly into THREE 9" cake pans. (Well-greased or non-stick). If you don't have three cake pans, bake the cake in batches.
Bake cakes until they are light brown on top and set in the middle - 22 to 25 minutes. Cool for 5 minutes in the pans, then turn out onto a rack to cool completely.
While the cakes are cooling, make the icing. In a medium sauce pan, combine the brown sugar and butter over medium heat, stirring constantly until the butter has melted and the sugar has dissolved - about 2 to 3 minutes.
Pour in the milk. Continue to stir and bring to a boil.
Remove the pan from heat and stir in the Mapleline flavoring. Set aside to cool slightly.
Place the sifted powdered sugar in a large bowl. Pour the butter mixture over the powdered sugar and mix by hand for 2 to 3 minutes until the icing is smooth.
While the frosting is still warm, but not hot, place one layer of the cake on a plate and pour icing over the center. Spred the icing out to the edges, then set the next cake on top. Repeat. Set the third cake on top and pour the remaining glaze over the cake.
Spread the icing to the edges of the top layer and let it naturally drip down the sides, or use your spreader to frost the sides - your choice! Sprinkle the top of the cake generously with coarsely chopped candied pecans.
Let the icing set for at least 30 minutes before cutting. Wonderful served with vanilla ice-cream. This cake will store well for a few days at room temperature, wrapped tightly.