If using radicchio Treviso tardivo as pictured here, trim off the bottom and separate the slender leaves. If using the round Chioggia or most other varieties of radicchio, cut the head in quarters, trim off the core, then cut the leaves into strips.

Arrange the radichio leaves on individual serving plates or in a salad bowl.

Peel the orange and trim off any stray filaments and pith. Separate the sections (you can cut each section in half lengthwise if very large) and arrange them on top or in between the radicchio leaves.

Crumble the shelled walnuts in your hand and sprinkle them here and there.

Drizzle with the olive oil, then sprinkle with salt to taste.

Serve right away.