Radicchio's main flavor characteristic is bitterness. Here, braised in a garlicky, prosciutto-enriched broth, the ruby-colored green's powerful bite melts to a mellow meatiness.
Bring a large pot of water to a boil for cooking pasta. Place a pasta-serving bowl and 4 individual pasta bowls in a warm oven.
Heat oil in a large nonstick skillet over medium-low heat. Add garlic and crushed red pepper. Cook, stirring, until tender and fragrant but not brown, 30 to 60 seconds. Add prosciutto and cook, stirring, until lightly browned, 2 to 3 minutes. Add radicchio, increase heat to medium and cook, turning with tongs, until wilted, 4 to 5 minutes. Season with pepper.
Pour in broth and bring to a simmer. Reduce heat to low and simmer, uncovered, until radicchio is tender, about 10 minutes.
Meanwhile, cook pasta in a pot of boiling salted water until al dente, 8 to 10 minutes. Drain and place in the warm serving bowl. Add sauce and 1/4 cup Parmesan; toss to coat. Taste and adjust seasonings. Serve immediately, passing remaining 1/4 cup Parmesan separately.
4 starch, 1 vegetable, 1 lean meat, 1/2 fat