Cook pasta according to package directions, omitting salt and fat. Drain pasta, reserving 3/4 cup cooking liquid.
Cook bacon in a large nonstick skillet over medium heat until crisp. Remove bacon from pan, reserving drippings in the pan; crumble. Add 1/2 cup chopped onion, bottled minced garlic, and chopped fresh thyme to drippings in pan; sauté 2 minutes. Stir in green peas; sauté 1 minute. Add green onions to pan; sauté 1 1/2 minutes. Add pasta, reserved cooking liquid, and half-and-half to pan; cook 1 minute or until thoroughly heated, tossing to combine. Remove from heat. Add butter, salt, and pepper to pan; toss until butter melts. Sprinkle with crumbled bacon and Parmesan cheese.