Drain the olives and pat them dry. With the help of the side of a large knife and the palm of your hand on top, squash the olives one or two at a time to release the pits. Peel away the flesh of the olives, and place them in a bowl. Discard the seeds.
Roughly chop the celery leaves and tear up the mint leaves and add to the olives.
Season with a generous amount of olive oil, a splash of red wine vinegar, a pinch of salt, and a few twists of pepper.
The Australian-Japanese cookbook author has lived in Florence (where a visit to a cheese farm once inspired her to start a food blog) for over 10 years with her Tuscan sommelier husband and two kids. Her third cookbook, Tortellini at Midnight, is out now.