⭐ Soy Milk + Lemon Juice or Vinegar (Best Vegan Option)
1 cup soy milk + 1 tablespoon lemon juice or white vinegar (let sit 5-10 minutes)Soy milk, when acidified with lemon juice or vinegar, curdles similarly to dairy milk, creating a buttermilk-like substitute. This acidity activates baking soda in brownies, promoting rise and tenderness.
Allow the mixture to sit for 5-10 minutes before use to ensure proper curdling. Soy milk’s protein content supports structure, but the flavor is more neutral and can slightly affect the final taste.
Brownies made with this substitute will have a slightly different flavor profile and may be less rich, but the texture and rise remain comparable to those made with buttermilk.