Rinse the blueberries and whole limes under running water.
Squeeze the juice from 2 limes.
Cut the remaining lime into wedges.
Set aside one-quarter of the blueberries for the topping.
Put the remaining blueberries, lime juice, pitted dates, almond butter and kefir into the blender.
With the lid secured, blend on low to combine, then gradually increase to high speed until smooth.
Divide the smoothie evenly among 3 glasses.
Top each glass with the reserved blueberries.
Serve the lime wedges alongside for an extra squeeze of juice to taste.
Storage and safety
Drink freshly blended. To save some, refrigerate immediately in a covered container at 4°C (40°F) or below and drink within 24 hours. Almond butter contains tree nuts; avoid it if you have a tree-nut allergy.