Ingredients

• 3 tablespoons olive oil
• 5 cups coarsely chopped red onions
• 4 cups thinly sliced leeks (about 4; white and pale green parts only)
• 2/3 cup dry red wine
• 1/3 cup balsamic vinegar
• 1/3 cup very finely chopped prosciutto (about 2 ounces)
• 2 tablespoons finely chopped fresh basil
• 1/4 teaspoon cayenne pepper
• 2 purchased 10-ounce fully baked thin pizza crusts
• 8 ounces Gorgonzola cheese, crumbled
• 1 tablespoon minced fresh rosemary

Instructions

1. Heat oil in heavy large pot over medium heat. Add onions and leeks and saut until tender, about 20 minutes. Add wine and vinegar. Cook until most of liquid evaporates and onions are brown, stirring frequently, about 20 minutes longer. Mix in prosciutto, basil and cayenne. Season to taste with salt and black pepper. (Can be made 2 days ahead. Cover and refrigerate.)
2. Preheat oven to 450°F. Place pizza crusts on 2 large baking sheets. Spoon onion mixture evenly atop crusts, leaving 1-inch border around edges. Sprinkle cheese and rosemary over onions.
3. Bake pizzas until cheese melts and begins to brown and crusts are crisp and golden, about 12 minutes. Cool on baking sheets 5 minutes. Cut into slices and serve.