3 tablespoons red-wine vinegar
1/2 teaspoon fine sea salt
6 tablespoons extra-virgin olive oil
1 pound radicchio zuccherino, cleaned and washed (mâche or arugula can be substituted)
1/2 cup sliced red onion
Freshly ground black pepper
3 hard-boiled eggs, peeled, cooled, and quartered
Whisk the vinegar, salt, and oil together in a large bowl until they form an emulsion. Add the radicchio and onion, and toss together. Add the freshly ground black pepper and the boiled eggs. Toss together well once more and serve.