For each Brussels sprout, cut the stem end off and remove 3-4 leaves. Rinse sprouts with cold water. Drain well.
Slice each sprout into thin circles and place in a large glass bowl. The 10 sprouts should produce about 3 cups shaved.
Place prosciutto slices in a sauté pan over med-low heat. Turn the slices after one to two minutes, or when the prosciutto begins to brown/crisp. When both sides of the prosciutto have crisped and most of the fat has been rendered out, remove from pan and set aside.
With pan still at a med-low heat, add 2 tablespoons olive oil and the sliced onions. Stir the onions to coat with the olive oil, gently scraping the bottom of the pan to release the flavor and fat leftover from the prosciutto. Sauté for 3-4 minutes or until onions are tender. Add 2 tablespoons of apple cider vinegar, 1/2 teaspoon of salt, and 1/2 teaspoon of black pepper to pan. Stir to combine and simmer for 2 minutes.
Pour the onion mixture over the shaved Brussels sprouts and toss together. The warm dressing will wilt the sprouts slightly and make them tender.
To the same pan, reduce the heat to low and add the walnuts. Toast the walnuts for 2 minutes or until fragrant. Remove from pan; set aside. Turn off the burner.
Cut the pear into quarters and remove core. Dice 3 of the quarters into small cubes. Slice the remaining quarter thinly.
Toss the shaved Brussels sprouts with the cooked wheat berries, diced pears, walnuts, and Parmesan cheese (if desired). Squeeze half a lemon over the top of the salad and toss.
Tear the crispy prosciutto into small pieces and scatter on top of the salad. Garnish with the sliced pears.