Return to heat just long enough to warm all the ingredients, about 5 minutes.
Using a hand blender or food processor puree soup until smooth.
Season to taste with salt and pepper.
Garnish as desired with thinned sour cream or yogurt and fresh basil.
Notes
*To get the random pattern of lines like you see in the photo dip a fork into well-stirred yogurt or sour cream, thinned with a bit of milk or cream, and splatter it over the soup in two directions. Garnish with fresh.