Preheat oven to 350F. Butter and flour a 9” x 5” loaf pan.
With an electric mixer, beat together butter, sugar, eggs, and marmalade on medium.
Add baking powder, baking soda, nutmeg, ginger, salt, and flour, beating on low until just combined.
Fold in zucchini and walnuts with a spatula. The mixture cannot be allowed to sit at this point or the sugar with draw all the moisture out of zucchini and produce more of a soggy brick.
Scrape into prepared loaf tin and level surface.
Bake for 60-70 minutes or until a skewer inserted in the middle comes out with just a few crumbs.
Cool in pan for at least 20 minutes before inverting. Allow to cool to until just warm or room temperature before slicing. Allowing the loaf to cool will keep more of the moisture in.
Store in the fridge and bring to room temperature or toast lightly before serving.