Vegetable Broth (Best Option)
1:1 (1 cup vegetable broth per 1 cup chicken broth)Vegetable broth works well as a substitute because it provides a similar liquid base and mild savory flavor that can enhance the depth of chocolate without clashing with the dessert's sweetness. The broth's water content helps maintain the proper batter consistency.
For best results, use a low-sodium or mild vegetable broth to avoid introducing bitterness or excessive saltiness. Taste the broth beforehand to ensure it is neutral enough for a sweet recipe.
Compared to chicken broth, vegetable broth keeps the brownies moist and tender while preserving the intended flavor profile, making it the most balanced alternative.