Refrigerate papaya chunks until very cold, at least 1 hour or overnight.

Place the chilled papaya chunks in a blender.

Add ice cubes to the blender.

Pour in nonfat plain yogurt (or soy yogurt or silken tofu).

Add finely chopped peeled fresh ginger to the blender.

Drizzle honey into the blender.

Squeeze the juice of two lemons into the blender.

Blend all ingredients until smooth.

If the mixture is too thick, add water, 1 tablespoon at a time, until desired consistency is reached.

Add fresh mint leaves and blend briefly to incorporate.

Pour the smoothie into glasses.

Garnish each glass with a sprig of fresh mint.

Serve immediately.