Put the raisins in a small bowl and pour boiling water over them to cover. Let stand until plump and soft, about 10 minutes. Drain.
Put the raisins, grapes, apricots, rosemary and onion in a large bowl. Add the lemon juice and stir in the olive oil. Season with salt and pepper.
Separate the radicchio into leaves, saving the heart for another use. Tear into bite size pieces and add to the dried fruit mixture along with the spinach. Toss well. Divide among 4 plates and top with the prosciutto, if using. Scatter the pine nuts over the top.
Frying rosemary on the branch removes its slightly soapy, bitter flavor so you can use more. Heat 1-inch oil in a deep saute pan to 350 degrees F. Deep-fry the rosemary for 30 seconds and drain on paper towels. Strip the leaves off the stems and crush the leaves in the paper towels to remove any excess oil. Mince and store in a clean, tightly sealed container. Use the fried rosemary to make a seasoned salt by adding it to a mixture of black pepper, dried lemon zest and salt.
Recipe courtesy of Michael Chiarello