Heat a large skillet over medium heat. Cook bacon until crisp; remove bacon using a slotted spoon, and drain on paper towels, reserving all drippings in skillet.
Add onion and garlic to hot drippings, and cook over medium heat, stirring often, for 10 minutes or until onion is tender. Sprinkle flour over onion mixture, and cook, stirring constantly, for 3 minutes. Whisk in milk, and cook, stirring constantly, for 6 minutes or until thickened. Remove skillet from heat, and add cheese, stirring until cheese melts.
Meanwhile, cook pasta according to package directions, adding peas during last 4 minutes of cooking time. Drain.
Stir pasta mixture into cheese sauce. Sprinkle with cooked bacon. Serve immediately.
*Frozen peas may be substituted for fresh. Just add them to the pasta 2 minutes later than the fresh peas.
Recipe by Paula Deen Magazine at https://pauladeenmagazine.com/creamy-shells-and-peas-recipe/