1. Cook tortellini according to package directions. Add peas during last minute of cooking. Drain pasta and peas; place in a large bowl.
2. While pasta cooks, melt butter in a medium saucepan. Add garlic; sauté 30 seconds. Combine half-and-half and flour in a small bowl, stirring with a whisk; add to pan. Bring to a simmer; cook 3 to 4 minutes or until thickened, stirring constantly with a whisk.
3. Toss half-and-half sauce, cheese, and remaining ingredients with pasta.