⭐ Plain Kefir (Best Gluten-Free Option)
1 cup plain kefir Quick tip: Kefir is naturally acidic and liquid, closely matching buttermilk's properties, resulting in tender, well-risen cookies.
Kefir is a fermented milk product with natural acidity and a similar consistency to buttermilk, which helps activate baking soda and tenderize the dough. Its probiotic content does not affect baking but adds a subtle tang.
Use plain, unsweetened kefir to avoid altering cookie flavor. Because kefir is slightly thinner than buttermilk, the dough consistency may be marginally looser, so monitor dough texture.
Cookies made with kefir will have a comparable tang and texture to those made with buttermilk, often with a slightly more pronounced fermented flavor.