Preheat the oven to 350 degrees F.
Mix the flour, baking soda, baking powder, salt, and sugar in a large bowl.
In a small bowl, mix orange juice, ginger, applesauce, vanilla and olive oil.
Add the wet ingredients to the dry and mix until everything is moistened. If the batter looks dry at this point, don't worry-- the zucchini will express tons of moisture.
Fold in the zucchini and the walnuts.
Grease and flour a fluted bundt pan, tube pan or 9-inch cake pan. Scrape the batter into the pan and make sure it's evenly spread.
Bake 45 minutes or until a toothpick in the center comes out clean. Remove to a rack, and unmold the cake after letting it stand 10 minutes.
While the cake is cooling, prepare the glaze by mixing the marmalade with 2 tbsp of water in a small saucepan. Heat until bubbly, then brush onto the warm cake. Let the cake cool thoroughly before slicing and serving.