1 large head (about 10-oz) radicchio, torn into bite-size pieces
8 ounce baby spinach leaves
1/2 cup kalamata olives, pitted
Directions
In a nonreactive salad bowl combine the vinegar, fennel seeds, 1/2 teaspoon salt, and several grinds of pepper. Whisk well to blend, then gradually whisk in the olive oil.
Trim a slice from the top and the bottom of a grapefruit. Then, stand the grapefruit upright on a work surface and, with a sharp knife (starting at the top and bringing the knife all the way down to the bottom), cut off all the skin and the white pith beneath. Repeat with the remaining grapefruit. Slice segments from the grapefruits, cutting between the membranes.
Add the grapefruit segments to the bowl with the dressing and toss to coat well; let stand at least 15 minutes or up to one hour so that juices from the grapefruit meld with the dressing. (The salad can be prepared to this stage one hour ahead; leave at room temperature.)
Add the radicchio, spinach, and olives to the salad bowl and toss to mix. Taste and add more salt and pepper if needed. Mound the salad on a salad plate.