Begin by gathering all the ingredients. If you are using frozen berries, there’s no need to thaw them as they will help give the smoothie a thick consistency.
Wash the mint leaves thoroughly and pat them dry. You can reduce the amount to suit your taste if you prefer a less pronounced mint flavor.
Combine the mixed berries, kefir, mint leaves, and honey or maple syrup in a blender if you’re using a sweetener. If you have chosen to add a banana for extra creaminess, peel and add it to the blender.
Blend the mixture on high speed until smooth. If the smoothie is too thick, add a little water or more kefir to reach your desired consistency.
If you used fresh berries and prefer a colder drink, add a handful of ice cubes and blend again until smooth.
Taste the smoothie and adjust the sweetness if necessary. Depending on the natural sweetness of the berries, you may not need additional sweetener.
Pour the smoothie into glasses and garnish with a few whole berries and a sprig of mint for a beautiful presentation.
Serve immediately and enjoy the refreshing flavors of your Berry Mint Kefir Smoothie!