Vegetable Broth (Best Option)
1:1 (1 cup vegetable broth per 1 cup chicken broth)Vegetable broth is a suitable substitute because it provides a similar liquid base with mild savory flavors that complement the cupcake batter's moisture needs. The broth contains salts and umami compounds that help maintain the batter's balance and tenderness.
When using vegetable broth, ensure it is low-sodium to avoid overpowering the sweetness. Taste the batter before baking to adjust sugar if needed. Avoid broths with strong herbaceous or bitter notes.
The final cupcakes will have a subtle savory undertone that enhances complexity without detracting from sweetness, resulting in a moist crumb similar to using chicken broth.