Blend the Base: In a high-speed blender, combine kefir, berries, lemon juice, mint, and sweetener (if using). Blend until smooth and creamy.
Adjust Texture: For a thinner drink, add a splash of water or more kefir. For thicker, more smoothie-like results, add a few ice cubes and pulse again.
Serve in Style: Pour into double-walled glasses or wine glasses. Garnish with a cluster of berries and mint or a white edible flower for an elite finish.
Optional Chill: Let sit in the fridge for 10–15 minutes to let flavors intensify. Stir before serving.