Remove stems from spinach and wash under cold running water. Pat dry thoroughly and place in a large salad bowl.
Discard the outer leaves of the radicchio. Cut radicchio in half lengthwise and remove the core. Wash and dry the leaves and slice into 1/2- to 1-inch strips. Add radicchio to salad bowl.
Discard the outer leaves of the endives if necessary. Halve endives, remove the core and then slice diagonally into 1/2- to 1-inch strips. Add to salad bowl. (Salad can be assembled up to this point and refrigerated a few hours ahead.) Just before serving, season with salt and pepper and toss with olive oil and vinegar. Adjust seasoning.
Place salad on individual dishes. Add cheese to the empty salad bowl, season lightly with salt and pepper and toss with whatever dressing is left in the bowl. Stir in just a little oil if needed. Spoon cheese over each salad and serve.
Note: This versatile, mild radicchio features an elongated head, reddish-maroon leaves and white ribs.
Prep time: 10 to 12 minutes
Sacramento chef Biba Caggiano recommends buying plenty of colorful salad greens and summer vegetables, checking your refrigerator for flavorful leftovers and turning it all into a beautiful salad. Here's one such salad.