Salad with Prosciutto and Caramelized Pears and Walnuts

Ingredients

• 2 cups fresh orange juice
• 2 tablespoons red wine vinegar
• 2 tablespoons finely chopped red onion
• 1 tablespoon white sugar
• 1 tablespoon white wine
• salt
• pepper
• 3/4 cup extra virgin olive oil
• 1 tablespoon butter
• 2 pears - peeled, cored and cut into wedges
• 1 cup walnut halves
• 1/2 cup white sugar
• 1/4 cup water
• 1/4 pound prosciutto, cut into thin strips
• 2 romaine hearts, rinsed and torn