How to Make It
Cook pasta according to package directions, adding carrots during last 3 minutes of cooking. Drain.
Heat oil in a medium saucepan over medium-low. Add shallots and garlic; sauté 5 minutes. Stir in flour; cook 30 seconds. Add milk to pan; bring to a simmer. Cook 5 minutes or until reduced to about 1 1/2 cups. Stir in salt, pepper, and 1/4 cup cheese until smooth. Add pasta mixture to milk mixture; toss. Top with breadcrumbs, remaining 1/4 cup cheese, parsley, and tarragon. Serve immediately.