I’ve made gluten-free zucchini bread at least a dozen times. But I didn’t have any zucchini and when I want to bake I want to bake, so I just substituted fresh fennel for the zucchini and added lemon because fennel already smells a little lemony. I crave fresh fennel pretty regularly so I’ve been keeping it on hand. Glad I am! I think as long as you’re substituting like for like, you should be good to go. And it worked! I just wish the fennel had come through more because it’s a lovely bright flavor. Think I’ll try it again with ground fennel seed.