Great, easy and extremely green summer soup! Feta and lemon zest topping with a drizzle of olive oil is an idea you can recycle almost with any soup. A trick of great soup masters.
And maybe you should plant that basil in a big pot in late spring, so you have your own supply over the summer. Other great lindy soups here.
Link to the recipe
Yotam Ottolenghi, Simple: A Cookbook, p. 53