Originally from Kraft.
3 C medium pasta shells, uncooked
4 slices bacon, chopped
2 T flour
2 C milk
2 C shredded sharp cheddar cheese, divided
¼ C grated Parmesan cheese
1 6 oz pkg baby spinach leaves
Preheat oven to 350°F.
Cook pasta in large saucepan as directed on package, omitting salt.
Meanwhile, cook and stir bacon in large saucepan until crisp. Use slotted spoon to remove bacon from pan, reserving drippings. Add flour to drippings; cook and stir 1 min or until bubbly. Gradually stir in milk. Bring to boil, stirring constantly; cook and stir 3 to 5 min. or until thickened. Add 1 cup cheddar and the Parmesan to saucepan; cook and stir 2 to 3 min. or until melted. Add cooked pasta, spinach, and bacon; mix well.
Spoon into 1-1/2-qt. casserole sprayed with cooking spray; top with remaining cheddar. Bake 20 min. or until heated through.