Water with a pinch of salt and dried herbs (Best Option)
1 cup water + 1/8 tsp salt + 1/8 tsp dried thyme or rosemary per 1 cup vegetable brothWater is the primary liquid component in vegetable broth, so it provides the necessary hydration for the zucchini bread batter. Adding a small amount of salt and dried herbs mimics the mild seasoning found in vegetable broth, supporting flavor complexity without overwhelming the delicate zucchini and spices.
To ensure success, dissolve the salt and herbs fully in the water before mixing with dry ingredients. Avoid adding too much herb to prevent bitterness or an herbal dominance.
Compared to vegetable broth, this substitute results in a slightly less complex flavor but preserves the moist texture and balance, making it the closest match in this context.