Summer Pasta Recipe: 2 medium-size yellow squash, 2 medium zucchini, 2 medium carrots, 1 small onion, 1 garlic clove, 3/4 cup vegetable broth, 5 tablespoons olive oil, 1 teaspoon salt, 1/2 cup chopped fresh basil, 1 (4-oz.) package prosciutto,  2 (8.8-oz.) packages pappardelle pasta, 1 tablespoon butter, 3 green onions,  8-oz. mascarpone cheese, 3/4 cup Parmesan cheese
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